Presentation on theme: "Ezra Wood, Scott Herndon, Luwi Oluwole, Simon Albo"— Presentation transcript:
1 Ezra Wood, Scott Herndon, Luwi Oluwole, Simon Albo 6/21/2011FLAIR workshop, Austin TXAcknowledgments: TCEQCharacterization of gas and particle emissions in the greater Houston area using the Aerodyne mobile laboratoryEzra Wood, Scott Herndon, Luwi Oluwole, Simon AlboT. Onasch1, E. Fortner1, J. Jayne1, J. Wormhoudt1, P. Massoli1, C. Kolb1, H. B. Lee2, M. Zavala3, L. T. Molina3, and W. B. Knighton4Aerodyne Research, Inc., Harvard University, Molina Center for Energy & Environment,Montana State University
2 Instrumentation CO, NO2, C2H4, HCHO (QC-TILDAS) O3, NO, CO2, SO2 aromatic VOCs, 1,3-butadiene,OVOCs (PTR-MS/NO+MS)O3, NO, CO2, SO2PAN (GC), VOCs (canisters) (UH)InstrumentationSize and chemically-speciated PM(Aerosol Mass Spectrometer) Particle number (CPC)Black Carbon (MAAP), extinctionPM size distribution (SMPS)Wind speed/directionActinic fluxGPS position
3 • quantification (pounds/hr) • location identification Goal:Conduct measurements that supportemissions characterization• quantification (pounds/hr)• location identificationMobile sampling:Texas City, Mont Belvieu, Ship ChannelStationary sites:Texas CityMont BelvieuU. Houston
5 Quantification of emissions from “traditional” combustion source: fuel-based emission factors Ship ChannelMay 28, 2009
6 Carbon balance method Emission Inventory 58 g NOx/kg fuel 18 ppb NOx / ppm CO2x total fuel consumptionEmissionInventory58 g NOx/kg fuel
7 HONO/NOx: 0.7 to 1.4% (similar to on-road diesel vehicles) Ship emission factorsPlume timeVessel name/typeNOxg/kg fueldOx/dNOxHCHOg/kgCO g/kgSO210:04Izumo Princess580.110:26Vega Spring612110:59Odfjell Seachem540.06122511:04UBC Bremen?800.0811:05Eitzen Chemical500.110.19483411:17Leyte Spirit890.070.17103711:24tug/ferry550.120.401.211:36300.09 – 0.150.1311:54Petropavlovsk440.1617WilliamsMSDc61.50.1511.06.3SSDb79.611.827.8This method works great with good winds. And when mobile, can usually drive around to make the winds work for you. Any decent research grade 1-second instrument can be incorporated into the mix. Daytime, nighttime both work. But still, wind has to be cooperative. Thus this is a good complement to the remote sensing methods that others will talk about.HONO/NOx: 0.7 to 1.4% (similar to on-road diesel vehicles)-based on comparison with UCLA iDOAS HONO/NO2 ratios
8 use carbon balance method … Flares:use carbon balance method ……with a few complicationsTCEQ’s Comprehensive Flare StudySeptember 2010:Assumed DRE = 0.98, more like 0.3 to 0.7ishHCHO/CO = 0.02 to 0.05 for propene flare• Destruction Removal Efficiency (DRE) vs. fuel-based emission factors • Assumption that most C ends up as CO, CO not valid
9 Emissions observed with ARI mobile laboratory during FLAIR 2009: 1) Useful correlations between combustion tracers (CO, CO2) and VOCs2) Obvious fugitive emissions3) Unclear – no obvious correlation between combustion tracersand VOCs, but can’t rule it out
10 1. (Useful VOC-COx correlations) Flare Emission Capture from Mobile Laboratory Mobile Lab Maneuvered HerePrevailing WindKnown Plant Flare P-200
11 Flare Emission Capture from Mobile Laboratory Prevailing WindThis is NOT self sampling.The incoming wind speed is 4-7 mph.VOC/CO ratio invariable, but CO2/CO changes – possibly from a clean CO2 source nearby.C2H4/CO2 ratios higher than highest superemitting on-road vehicleKnown Plant Flare P-20011
12 Flare Emission Capture from Mobile Laboratory Prevailing WindThere are different CO2 to CO ratios – there seems to be only one VOC to CO ratio & HCHO/CO is RIGHT IN LINE WITH TCEQ Comprehensive Flare Study!!myriad other sources of CO2Ethylene to formaldehyde ratio is high suggesting ethylene is vent gas (but don’t know for sure).DRE def less than 98%.Known Plant Flare P-200Carbon balance methods with a guess about vent gas composition:DRE = 94% (88% - 96%)12
15 3) No obvious correlation between combustion tracers and VOCs, but can’t rule out low DRE flare vs. leak
16 3) No obvious correlation between VOCs and COx – low DRE flares? (VOC to CO/CO2 ratio believable if DRE < 30%).C2H4 of 200 ppb = 0.4 ppm of C. Low DRE flare could give just a ppm or 2 of CO2 – within the atmospheric noise.
17 The Aerodyne Inverse Modeling System (AIMS) DriverSCIPUFFSCIPUFF TL/AdjointMinimizationalgorithmObs. Data(MET, Sensors)# of sources,Emission rates,Locations,Start andEnd times.Given knowledge of the wind history, determine emission source parameters that when applied in atmospheric dispersion model yield pollutant concentration profiles that are most consistent with observed profilesAerodyne Research, Inc.
18 Inversion model results Texas City15 pounds/hr benzene sourceidentified by inversion modelWIND
19 Stationary data: SO2 “upwind” from courthouse site (TC) Stationary data was useful too. Data points projected 5 min back, linearly. Known regeneration facility nearby.
20 HCHO: same spatial signature filtered day/night
21 Consistent HCHO/SO2 ratio Each marker (color) is a different transect (90 total). Occasionally there is HCHO w/ little SO2, but usually a consistent HCHO/SO2 ratio.
22 HCHO: Primary vs. secondary? C2H4 + OH → → 1.43 HCHOphotochemical age (OH exposure):What else can we learn from these downwind observations? WE can constrain the photochemical age (OH exposure) by examining the HCHO/C2H4 and HCHO/propene ratios…22
23 Primary HCHO in Texas City? slope implies [OH] = 2 ×107 to 4 × 107 molecules/cm3→ evidence for primary HCHO
24 Primary HCHO from Chevron? C2H4 (ppb)HCHO (ppb)Slope = 0.02Slope and transit time imply [OH] = 1.33 × 106 molecules cm-3 at 07:20 CST5/21/2009 → no evidence for primary HCHO
25 1,3-butadiene mapping (Ship Channel) Goodyear facility – known source of 1,3-butadiene. Were able to measure with Berk Knighton’s “special” 1-second PTR. Luwi will talk more about this facility.WIND
26 1,3-butadiene, styrene1,3-butadiene and styrene emitted from different locations.
27 Summary • Mobile measurements useful for locating and quantifying emission sources• Rich dataset:Marathon flare DREShip emission factorsWinfree road Ethylene leakPrimary HCHO emissions from Texas City facililtyEthylene, propylene emission from Chevron (Mont Belvieu)1,3-butadiene, styrene from Goodyear
30 P(OH) = L(OH)Total OH loss rate = 47.3 s-1, and is dominated by reaction with C2H4.This yields an OH concentation of 1.6 × 105 molecules/cm3. Since the HO2 + NO term is obviously not zero, this number should be considered a lower limit to the true OH concentration. This value is likely higher than the [OH] in non alkene plume air considering the time of day (06:12 local time). Further analysis will address the likely range of values for the HO2 + NO term.
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