ORD Testing to Support Development ofEPA Performance Specification 18 for HCl CEMSOffice of Research and DevelopmentNational Risk Management Research Laboratory.38th Stationary Source Sampling & Analysis for Air Pollutants ConferenceMarch 4th, 2013Point Clear, ALJeff Ryan and Ed BrownUS EPA – Office of Research and DevelopmentPeter KariherARCADIS US, IncTopics•Update on HCl measurements testing•Update on HCl gas standards•Traceability Protocol for HCl Evaporative Generators12Reference Method AgreementM26A Avg.ppmv (wet)FTIRppmv (wet)AbsoluteDifferenceppmvRelativeDifference%Fuel/Coal Type RDNatural gas 0.27 6.3% 0.19 0.08 33.6%Natural gas 0.59 1.1% 0.59 0.00 0.1%Natural gas 2.02 1.7% 1.98 0.04 2.1%Bituminous 23.36 0.7% 24.37 1.01 4.2%Bituminous 25.06 0.7% 25.87 0.81 3.2%Bituminous 20.15 3.7% 25.71 5.56 24.3%Bituminous 23.42 0.3% 26.46 3.04 12.2%PRB 3.44 1.0% 3.82 0.38 10.4%PRB 3.58 0.0% 3.99 0.41 10.9%PRB 4.08 8.4% 4.25 0.18 4.3%Lignite 2.03 9.4% 2.34 0.31 14.3%Lignite 2.33 0.3% 2.52 0.20 8.2%Bituminous 30.35 2.1% 33.14 2.79 8.8%Bituminous 29.86 1.1% 32.30 2.45 7.9%Average 2.6% Average 10.3%Gas Standard Testing•Compressed Gases:–Have come a long way•Lower levels•Stable–Now being used for PS-18Testing–Evaluating dilution for low levels3•Hovacal/Evaporative Generators:–Alternative to compressed gases–Testing to evaluate comparability–Testing to determine uncertainty of gases generated–Testing to inform Traceability Protocol3/26/2013 1/17/2014AirgasTagValueFTIRMeasuredValue AgreementFTIRMeasuredValue Agreementppm ppm % ppm %1.843 1.846 0.2 1.892 2.74.600 4.525 -1.6 4.598 0.09.280 9.439 1.7 9.237 -0.5Wet and Dry HCl Gas ComparisonWet Gas (HovaCAL) - Moisture Fixed at 8%Gas Cylinders with Gas DividerSet PointConc.(ppmv)TheoreticalConc.(ppmv)FTIRMeasured Conc.(ppmv)RelativeDifference%RSD(%)0.5 0.53 0.49 -7.9% 6.6%1 1.02 1.02 -0.3% 4.3%2 2.09 2.06 -1.6% 1.8%5 5.31 5.37 1.2% 0.9%9 9.00 8.79 -2.3% 1.0%Set PointConc.(ppmv)TheoreticalConc.(ppmv)FTIRMeasured Conc.(ppmv)RelativeDifference%RSD(%)0.5 0.45 0.44 -2.3% 8.5%1 0.90 0.88 -2.0% 4.1%2 2.25 2.25 0.2% 1.9%5* 4.60 4.49 -2.4% 1.8%10* 9.28 9.15 -1.4% 0.5%* = Gas direct from cylinderNIST Status•Establishing capabilities to provide traceability–Developed multiple working ref HCl gas cylinders(1, 8-14ppm)•Primary HCl standard = 400 ppm–NIST concentrations confirmed by VSL(within uncertainties)–Have characterized HCl RGMs from 2 gas vendors•HCl concentrations 8-12 ppm•Uncertainties ~1.5%, one year certification (for now)•RGMs will be returned to vendors soon–Recognize the need to expand the range of concentrations•Targeting vendor supplied concentrations from 0.5 ppm to > 500 ppm5Gas Vendor Status•Multiple gas vendors are now providing low level(<10 ppm) HCl gas standards–Targeting <1 ppm gases•Based on NIST RGM uncertainties, out-the-door uncertaintiesfor commercial HCl gases expected to bewell below 5%•Current commercial gases have agreed well with FTIRreference spectra and have been used to conduct fieldCalibration Error testing•Examining stability for long-term certifications•Evaluating HCl-specific regulators for improved performance•Discussing guidance for cylinder use6HCl Gas Standard Availability7Low Mid HighSpan 10% 30% 50% 60% 80% 100%ppm ppm ppm ppm ppm ppm ppm20.2 0.61.0 1.21.6 2.050.51.5 2.5 3.0 4.0 5.0101.03.0 5.0 6.0 8.0 10.0202.0 6.0 10.0 12.016.0 20.0505.0 15.025.0 30.0 40.0 50.0GasesavailablefromNISTandvendorsGasesavailablefromNISTGasesavailablefromvendorsGasesavailablefromevaporativegeneratorsonlyEPA Traceability Protocol for Qualification andCertification of Evaporative Hydrochloric Acid GasGenerators and Humidification of Gases from Cylinders•Qualification Tests–Performed by manufacturer–Demonstrates the adequacy of each model, not each unit–Manufacturer’s Disclosure defines for customer the range ofconditions under which the model can operate reliably•Certification–Unit-specific – serial number recorded on documentation–Performed by manufacturer, but may be repeated by customer orthird-party if in-field recertification becomes necessary–Defines the relationship between reported concentrations andcorresponding NIST-traceable concentrations.Qualification Tests (tentative)•Setpoint Repeatability (hysteresis)•Thermal Stability•Back Pressure•Supply Pressure•Line VoltageCertification Assumptions•Assumptions (based on qualification tests)–The “mass balance” holds – no leaks, losses, or conversions–All component measurement devices deliver stable and repeatablereadings over their range of operation–The performance of the overall calibration gas delivery device isreproducible over its range of operating conditionsCertification•NIST-traceable reference devices/materials required–HCl source material – liquid or gaseous standard with traceableconcentration–Gas flow(s) – independent traceable standard(s), with unexpiredcertification, covering the full range of gas flows required–Liquid flow(s) – usually performed by gravimetric means, using abalance calibrated with NIST-traceable weights•Output Verification–Demonstrates that the actualHCl output concentration agrees withthe calculated concentration from the NIST-traceable inputs–Comparison with NIST-traceable bottled gasUncertainty of Certified Output•Calculated by propagation of uncertainty from inputconcentrations and operational measurements–Concentration of certified HCl liquid or gas standard–Uncertainty of dilution process (if used) to make liquid workingsolution from commercial standard solution–Liquid and gas feed rates, including reproducibility•Standard uncertainties of these components arecombined to calculate combined uncertainty.•Combined uncertainty is multiplied by a coverage factorof 2 to get expanded uncertainty.13Calculated Uncertainty Components2/12222FACSWSUUUUWhere:UWS= Uncertainty in the concentration of the working solution (%)UCS= Expanded uncertainty of the commercial standard, with a coveragefactor of 2 (%)UA= Uncertainty of the aliquot weight or volume (%)UF= Uncertainty of the final, diluted standard weight or volume (%)Liquid HCl Concentration: 2/122122)1(1LFDJLFDLFDUJJUjJjjLFDLFR 2/122122)1(1GFDJGFDGFDUJJUjJjjGFDGFRLiquid Feed Rate:Where:ULFR= Uncertainty of the liquid feed rate (%)J= Number of independent liquid feed determinationsULFD= Uncertainty of an independentliquid feed determination (%)LFR= Liquid feed rate as determined (g/min or mg/min)Where:UGFR= Uncertainty of the gas feed rate (%)J= Number of independentgas feed determinationsUGFD= Uncertainty of an independent gas feed determinationGFD= Gas feed rate as determined (l/min or ml/min)Gas Feed Rate:14Expanded Combined Uncertainty 2/122222LFRGFRWSOUTUUTFRGFRUUWhere:UOUT= Uncertainty in the delivered concentration (%)UWS= Uncertainty in the concentration of the working solution (%)GFR= Gas feed rate measurement (dslpm)TFR= Total flow rate, including dry gasand evaporated liquid measurements (slpm)UGFR= Uncertainty of the gas feed rate (%)ULFR= Uncertainty of the liquid feed rate (%)GFRMWVLFRTFRWstdˆWhere:LFR= Liquid feed ratemeasurement (g/min)= Standard molar volume from ideal gas law (22.4 liters/mol @ 0°C, 1 atm)MWW= Molecular weight of water (18.016 grams/mol)stdVˆJLFDLFRJjj1JGFDGFRJjj115Example Uncertainty Calculation%25.022/1222FACSWSUUUUUCS= 0.50%UA= 0.03%UF= 0.04%Liquid HCl Concentration: %21.0)1(12/122122LFDJLFDLFDUJJUjJjjLFDLFR %88.0)1(12/122122GFDJGFDGFDUJJUjJjjGFDGFRLiquid Feed Rate:J= 3ULFD= 0.009% 0.016% 0.013%LFD= 0.5218 g/min 0.5283 g/min 0.5267 g/minJ= 2UGFD= 0.4% 0.4%GFD= 8.812 slpm 8.708 slpmGas Feed Rate:16Example Uncertainty Calculation %8.122/12222LFRGFRWSOUTUUTFRGFRUUUWS=0.25%UGFR=0.88%ULFR=0.21%lpmGFRMWVLFRTFRWstd413.9ˆLFR= 0.5256 g/min= 22.4 liters/molMWW= 18.016 grams/molGFR= 8.760 lpmstdVˆQuestions ...17