Transcript
Electrical Mobility Measurements of
Agglomerate Particulate Matter
Jim DunsheeMS Thesis Defense
November 11th, 2015
Slide 2
Historical Perspective: Particle Uncertainty
“…but how many particles are really present under any conditions, and how the number varies, we have at present very little idea.”
- John Aitken, 1888
SOURCES: Aitken, 1888; Wellcome Library; Seinfeld & Pandis, 2006
≥10 microns (µm)visible to the human eye
Slide 3
Particulate Matter (PM)
IMAGE SOURCE: ciese.org
“A complex mixture of extremely small particles and liquid droplets” (US EPA)
PM10 PM2.5
Slide 4
PM & Health
• Class 1 Carcinogen• No evidence of safe exposure level
(World Health Organization, 2013)
IMAGE SOURCE: alencorp.com (Everything You Need to Know About Airborne Particulate Matter)
Slide 5
Particle Size Distribution
Low
← N
umbe
r → H
igh
Small ← Particle Diameter → Large
Slide 6
Diesel PM Size Distribution
IMAGE SOURCE: Kittelson,, 1998
Slide 7
Spark vs. Compression Ignition Engine Emissions
IMAGE SOURCE: dieselnet.com
SI engine with catalyst
Diesel engine (100%)
Rela
tive
Emiss
ions
(%)
Slide 8
Engine Cycles
Gasoline - Otto Cycle• Spark Ignition (SI)• Homogeneous combustion• Burns “rich”
• Air-fuel ratio < stoichiometric
Diesel - Diesel Cycle• Compression Ignition (CI)• Heterogeneous combustion• Burns “lean”
• Air-fuel ratio > stoichiometric
IMAGE SOURCE: Reactive Flow Modeling Laboratory (rfml.kaust.edu.sa)
Slide 9
Diesel PM/NOx TradeoffDiffusion Flame Combustion
Oxidation• Decreases soot (PM)• Increases NOx
SOURCES: Kittelson & Kraft, 2014; Dec, 1997
Slide 10
Diesel PM Formation
IMAGE SOURCES: Khalek, 2006; Twigg & Phillips, 2009
ElementalCarbon (EC)
OrganicCarbon (OC)
Slide 11
PM Formation by Particle Size
IMAGE SOURCE: Guarieiro & Guarieiro, 2015
Re-entrainmentEngine wear
Slide 12
Diesel Properties
Medium petroleum distillates: C8 – C21
Ultra-Low Sulfur Diesel (ULSD):Naturally occurring sulfur (a lubrication agent)reduced to 15ppm = less soot formation
~75% Alkanes ~25%
May result in toxicaromatic emissions
IMAGE SOURCE: criticalfueltech.com
Slide 13
Biodiesel PropertiesFatty Acid Methyl Esters (FAMEs)
Potential to reduce PM:• Oxygen content of molecule (complete combustion/soot oxidation)• Absence of sulfur• Absence of aromatic compounds
(Lapuerta et al., 2007)
IMAGE SOURCE: biofuelsystems.com/biodiesel-chemistry
Slide 14
Biodiesel PM PropertiesChung et al., 2008 (diesel generator):Irregular compact particles with more organic carbon relative to ULSD
SOURCE: Chung et al., 2008
Diesel
Biodiesel
Slide 15
PM MeasurementThe Gravimetric Method
Operational Definition:“mass collected on a filter” under specified conditions(Swanson et al., 2012)
MassVolumeUnits: Mass Concentration (µg/m³) =
Issues: 1) Temporal Resolution
requires time to collect sample2) Measurement Error
low modern vehicle emission rates
Diesel PM Emission Standards
Slide 16SOURCES: (a) Twigg & Phillips, 2009; (b) Vouitsis et al., 2003
(b) US and EU diesel PM emission limits for heavy-duty vehicles from 1992-2010
(a) EU legislated diesel PM emission limits for passenger cars from 1983-2010
Slide 17
Gravimetric Accuracy
SOURCE: Vouitsis et al., 2003; ACEA report 99000524
Note: emission rates and standards for heavy-duty engines
Slide 18
New Method: IPSD (Integrated Particle Size Distribution)
Basic procedure1. Measure particle size
distribution (PSD) by number
2. Assume spherical particles to calculate volume
3. Apply size dependent density values to calculate mass
m = ρVmass = density x volume
Low
← N
umbe
r →Hi
gh
= rV=
43 π r
3
IMAGE SOURCES: vironova.com, rkm.com.au
Method formalized by Liu et al. (2009)
• Light-duty vehicles (gas & diesel)• Empirically based particle effective density values• Good correlation (R² = 0.79) between IPSD and
Gravimetric• Systematic bias (MassIPSD = 0.63 x MassGrav)
Slide 19
Li et al. (2014) : IPSD Study
Slide 20
Problem With PSD Measurements (EEPS)
Discrepancies reported between
Engine Exhaust Particle Sizer (EEPS or FMPS)and Scanning Mobility Particle Sizer (SMPS)for agglomerate particles (e.g., diesel soot)(Kaminski et al., 2013; Quiros et al., 2014; Zimmerman et al., 2014)
Slide 21
SMPS (Scanning Mobility Particle Sizer)
IMAGE SOURCES: Guha et al., 2012; redwoodareahospital.org
Considered the “gold standard” particle sizing/counting system
Slide 22
SMPS: Bipolar Diffusion ChargingRoughly independent of particle morphology
Note: Particle charging efficiency drops dramatically below 20nm for Boltzmann distribution (shown). Fuchs charging theory is better for Dp < ~50nm.
Charge distribution forms over time (Hinds, 1999):
< -3 -3 -2 -1 0 +1 +2 +3 > +30.01 0.007 0.3 99.3 0.30.02 0.104 5.2 89.6 5.20.05 0.411 0.6 19.3 60.2 19.3 0.60.1 0.672 0.3 4.4 24.1 42.6 24.1 4.4 0.30.2 1.00 0.3 2.3 9.6 22.6 30.1 22.6 9.6 2.3 0.30.5 1.64 4.6 6.8 12.1 17.0 19.0 17.0 12.1 6.8 4.61.0 2.34 11.8 8.1 10.7 12.7 13.5 12.7 10.7 8.1 11.82.0 3.33 20.1 7.4 8.5 9.3 9.5 9.3 8.5 7.4 20.15.0 5.28 29.8 5.4 5.8 6.0 6.0 6.0 5.8 5.4 29.8
10.0 7.47 35.4 4.0 4.2 4.2 4.3 4.2 4.2 4.0 35.4
Percentage of particles carrying theindicated number of charges
Dp
(µm)
AverageNo. of
Charges
IMAGE SOURCE: palas.de/en/product/kr8557
Slide 23
EEPS (Engine Exhaust/Fast Mobility Particle Sizer)
Unipolar charger:
SOURCES: Krinke & Zerrath, 2011; TSI, 2015
Slide 24
EEPS: Unipolar Diffusion Charging
Default calibration underestimatescharge for agglomerates
IMAGE SOURCE: TSI, 2015
TSI Solution:New, empirically based, EEPS data inversion matrices
Problem:EEPS unipolar charge distributioncalibrated for spheres (emery oil)
turbocharged, 4 cylinder, 4.5L, 75kW, Tier 3 diesel engine fueled with BP6 diesel fuel with a sulfur content of 6ppm
Slide 25
New EEPS Matrix Development by TSI
SOURCE: TSI, 2015
Slide 26
New EEPS Matrices: Soot & Compact
Instrument matrix calibrated for soot Comparison of current matrices at 420nm and 42nm electrometer columns
Slide 27
Soot Matrix Results: Heavy-duty Engine
IMAGE SOURCE: TSI, 2015
Low Load:
High Load:
Number Volume
Slide 28
Soot Matrix Results: Light-duty Engine
IMAGE SOURCE: TSI, 2015
GM A20DTH 2.0L light duty turbo charged diesel engine
Slide 29
GMD Agreement with Soot Matrix
No longer underestimates largeragglomerate particles (Dp > ~100nm)
IMAGE SOURCE: TSI, 2015
1) How accurate are new EEPS matrices for various vehicle exhaust particles?a) Biodiesel - unique morphology/chemical composition?b) Transient drive-cycle
2) Do new EEPS matrices improve mass estimates with IPSD method?a) IPSD vs. Gravimetricb) Transient events (e.g., cold-start)
Slide 30
Research Questions?
Slide 31
Current Study
Experiments/Dataset 1: EEPS Evaluation
Experiments/Dataset 2: Cold-start EmissionsEEPS measurements for first 30sec of engine
start at10, 15, and 25°C (nominally)
Slide 32
Data Collection Sequence
Event Setting Duration
Instrument Blank (preIB) Instrument on HEPA filter ≥10minTunnel Blank (preTB) Dilution System On ≥10minEngine Idle Engine On 7.5minEngine Warm-up 3300rpm, 40 or 60% Throttle 7.5minTest Cycle Various ~90minEngine Cool-down (Idle) Engine On 7.5minTunnel Blank (postTB) Dilution System On ≥10minInstrument Blank (postIB) Instrument on HEPA filter ≥10min
Test Cycles1) Steady State (75% engine load)2) Transient (60min) + 3x10min Steady State Phases
- Depicted in Slide 37
Slide 33
Experimental Setup
Engine exhaust
Dry, filtered air
Key:
DifferentialPressure Gage
Temp. ControlSetpoint (°C)
2 stagediluter
Diluted SampleDilution Ratio ~80:1
Engine drive cycle and dilution system developed by by Tyler Feralio (image credit)
Engine:Volkswagen 1.9L SDi (similar to Euro II LDD)• 4 Cylinders• No aftertreatment devices
Slide 34
Fuel Properties
SOURCE: GC-MS analysis conducted by John Kasumba
ULSD (0.81g/cm³) Soybean Biodiesel (0.86g/cm³)
Slide 35
Density Distribution
Slide 36
Quality Assurance: SMPS & Filters
SMPS (units: #/cm³)
90min Filter Blanks (Tunnel)N 5
Avg 4 µg/m³StDev 2.4
Minimum value from tests:35.5 µg/m³
Reported as: MEAN [95% One-sided Upper Confidence Limit]
Slide 37
QA: EEPS Dataset 1 – Box Plots
Slide 38
QA: EEPS Dataset 1 – Detection Limit
EEPS pre-test instrument blank data
Slide 39
ULSD Steady State PSDsLog-log plot Semi-log plot
Slide 40
ULSD Modal Fit Parameters
Slide 41
Xue et al. (2015): Generator on ULSD
SOURCE: Xue et al., 2015
Slide 42
ULSD PM Mass Data
Slide 43
Soot vs. Default: Transient Cycle w/ ULSD
Slide 44
ULSD Transient Phase: Fractional Contributions
Slide 45
ULSD Steady State: Fractional Contributions
Slide 46
Betha & Balasubramanian (2011): ULSD Particle Fractionation
Idle 30% 70% 100%Engine Load (%)
100%
80%
60%
40%
20%
0%
Parti
cle
Num
ber F
racti
on (%
)
Nanoparticles(>50nm)Ultrafine(50-100nm)Fine(>100nm)
FMPS data (i.e., Default EEPS matrix) for diesel generator exhaust
SOURCE: Betha & Balasubramanian, 2011
Slide 47
Biodiesel Steady State PSDsLog-log plot Semi-log plot
Slide 48
Biodiesel Modal Fit Parameters
Slide 49
Xue et al. (2015): Generator on Biodiesel
SOURCE: Xue et al., 2015
Slide 50
Biodiesel PM TrendGravimetric PM data by biodiesel blend for the light-duty diesel engine from this study (dashed line & blue data points)
General trend reported by EPA (2002) - solid line and black data points
Giakoumis et al. (2012)
Majority of data for EPA (2002) & Giakoumis et al. (2012) for heavy-duty diesel engines
Bielaczyc et al. (2009)data for a LDD engine
Slide 51
Biodiesel PM Mass Data
Slide 52
EEPS Report CardKeySP: Satisfactory ProgressUP: Unsatisfactory Progress
IMAGE SOURCE: diplomabuy.com
Slide 53
QA: EEPS Dataset 2 – Box Plots
Slide 54
QA: EEPS Dataset 2 – Detection Limit
EEPS pre-test instrument blank data
Slide 55
ULSD Cold-start Emissions
Slide 56
Cold-start: Fractional Contributions
Slide 57
Sakunthalai et al. (2014): ULSD Cold-starts
Cambustion Differential Mobility Spectrometer (DMS500) data for LDD engine exhaust
SOURCE: Sakunthalai et al., 2014
• EEPS Soot Matrix• Good agreement for ULSD (SMPS and Filter)• Applied to cold-start emissions
• Biodiesel Exhaust Particles• Not characterized well by EEPS
• Poor agreement with SMPS and Filter
Slide 58
Conclusions
• Biodiesel exhaust particle effective density
• Additional EEPS matrices• Or user calibration
• EEPS evaluation for biodiesel blends
• EC/OC analysis by engine load• Compared to particle size fractionation trend
Slide 59
Future Work
UVM Transportation Air Quality LabBritt HolménTyler Feralio
John KasumbaKaren Sentoff
Yao Tan
Acknowledgements
Thank You
Questions & Answers
Betha, Raghu, and Rajasekhar Balasubramanian. "Particulate emissions from a stationary engine fueled with ultra-low-sulfur diesel and waste-cooking-oil-derived biodiesel." Journal of the Air & Waste Management Association 61.10 (2011): 1063-1069.
Bielaczyc, Piotr, and Andrzej Szczotka. A study of RME-based biodiesel blend influence on performance, reliability and emissions from modern light-duty diesel engines. No. 2008-01-1398. SAE Technical Paper, 2008.
Chung, A., A. A. Lall, and S. E. Paulson. "Particulate emissions by a small non-road diesel engine: Biodiesel and diesel characterization and mass measurements using the extended idealized aggregates theory." Atmospheric Environment 42.9 (2008): 2129-2140.
Dec, John E. A conceptual model of di diesel combustion based on laser-sheet imaging*. No. 970873. SAE technical paper, 1997.
EPA, “A comprehensive analysis of biodiesel impacts on exhaust emissions (EPA420-P-02-001)." United States Environmental Protection Agency (2002).
Giakoumis, Evangelos G., et al. "Exhaust emissions of diesel engines operating under transient conditions with biodiesel fuel blends." Progress in Energy and Combustion Science 38.5 (2012): 691-715.
Guarieiro, Lílian Lefol Nani and Aline Lefol Nani Guarieiro (2015). Impact of the Biofuels Burning on Particle Emissions from the Vehicular Exhaust, Biofuels - Status and Perspective, Prof. Krzysztof Biernat (Ed.), ISBN: 978-953-51-2177-0, InTech, DOI: 10.5772/60110.
Guha, Suvajyoti, et al. "Electrospray–differential mobility analysis of bionanoparticles." Trends in biotechnology 30.5 (2012): 291-300.
Hinds WC. Aerosol Technology: Properties, Behavior, and Measurement of Airborne Particles, 2nd edn. John Wiley & Sons, Inc, New York, 1999.
Holmén, B. A.; Feralio, T.; Dunshee, J.; Sentoff, K. Tailpipe Emissions and Engine Performance of a Light-Duty Diesel Engine Operating on Petro- and Bio-diesel Fuel Blends. 2014.
Kaminski H, Kuhlbusch TAJ, Rath S, Götz U, Sprenger M, Wels D, Polloczek J, Bachmann V, Dziurowitz N, Kiesling HJ, et al. Comparability of mobility particle sizers and diffusion chargers. Journal of Aerosol Science. 2013;57:156-178
Khalek, Imad A. "The particulars of diesel particle emissions." Technology Today 27.1 (2006): 2-5.
Kittelson DB. “Engines and nanoparticles: a review.” J. Aerosol Sci.1998; 29: 575–88.
Kittelson, David, and Markus KRAFT. "Particle Formation and Models in Internal Combustion Engines." United Kingdom: University of Cambridge (2014).
Slide 62
References (1 of 2)
Krinke, Thomas and Axel Zerrath. “EEPS/FMPS: From Raw Data to Size Distribution.” Presentation (Sep. 2011).
Lapuerta, Magin, Octavio Armas, and Jose Rodriguez-Fernandez. "Effect of biodiesel fuels on diesel engine emissions." Progress in energy and combustion science 34.2 (2008): 198-223.
Li, Yang, et al. Determination of Suspended Exhaust PM Mass for Light-Duty Vehicles. No. 2014-01-1594. SAE Technical Paper, 2014.
Liu, Z. Gerald, et al. "Comparison of strategies for the measurement of mass emissions from diesel engines emitting ultra-low levels of particulate matter." Aerosol Science and Technology 43.11 (2009): 1142-1152.
Park, Kihong, et al. "Relationship between particle mass and mobility for diesel exhaust particles." Environmental science & technology 37.3 (2003): 577-583.
Quiros, David C., et al. "Particle effective density and mass during steady-state operation of GDI, PFI, and diesel passenger cars." Journal of Aerosol Science (2014).
Sakunthalai, Ramadhas Arumugam, et al. Impact of Cold Ambient Conditions on Cold Start and Idle Emissions from Diesel Engines. No. 2014-01-2715. SAE Technical Paper, 2014.
Seinfeld J. H. and Pandis S. N. (1998) Atmospheric Chemistry and Physics: From Air Pollution to Climate Change, 1st edition, J. Wiley, New York.
TSI (2015). Updated inversion matrices for engine exhaust particle sizer (EEPS) spectrometer model 3090.
Twigg, Martyn V., and Paul R. Phillips. "Cleaning the air we breathe-Controlling diesel particulate emissions from passenger cars." Platinum Metals Review53.1 (2009): 27-34.
Vouitsis, Elias, Leonidas Ntziachristos, and Zissis Samaras. "Particulate matter mass measurements for low emitting diesel powered vehicles: what's next?." Progress in Energy and Combustion Science 29.6 (2003): 635-672.
Xue, Jian, et al. "Comparison of vehicle exhaust particle size distributions measured by SMPS and EEPS during steady-state conditions." Aerosol Science and Technology 49.10 (2015): 984-996.
Zimmerman, Naomi, et al. "Comparison of three nanoparticle sizing instruments: The influence of particle morphology." Atmospheric Environment86 (2014): 140-147.
Slide 63
References (2 of 2)
top related