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Wir schaffen Wissen – heute für morgen
Mitigation of secondary organic aerosol formation from wood burning emissions by catalytic removal of aromatic hydrocarbons
Simone M. Pieber1,2 ,Anastasios Kambolis1, Davide Ferri1, Deepika Bhattu1, Emily A. Bruns1,
Martin Elsener1, Oliver Kröcher1,3, André S.H. Prévôt1, Urs Baltensperger1
1PSI/Switzerland, 2now at Empa/Switzerland, 3EPFL/Switzerland(e-mail: [email protected])
Simone M. Pieber 2
MOTIVATION METHODS RESULTS CONCLUSIONS
June 20, 2018
0%
20%
40%
60%
80%
100%
(Lanz et al., ACP., 2010)
52%
12%
35%
Average organic PM components in Winter from various sites in central Europe
SOA
POA(wood burning)
POA(traffic)
Residential logwood burning emits
harmful volatile organic compounds (VOC)
toxic carbon monoxide (CO)
greenhouse gases (CH4, CO2)
fine particulate matter (PM) with complex, adverse effects
emissions form secondary organic aerosol (SOA)
Simone M. Pieber 3
MOTIVATION METHODS RESULTS CONCLUSIONS
June 20, 2018
?
?
by-pass(fresh emissions)
catalyticallycoated monolith
OH
Simone M. Pieber 4
MOTIVATION METHODS RESULTS CONCLUSIONS
June 20, 2018
Coated monolithin quartz glass reactor:
1) Pt/Al2O32) Pt/CeO2‐Al2O3
1:8, 80°C
3 m3 Teflon Chamber
CO2 3400‐10500 ppmCO 360‐1100 ppmCH4 65‐220 ppm
NMHC 75‐270 ppmCArHC 70‐320 ppmC
H2O 1 vol%
POA 500‐1500 µg m‐3
BC 5000 µg m‐3
LogwoodAppliance
SilcoT
ekstee
lsam
plinglin
es(80°C)
1:8, 150°C Instruments
PTR‐ToF‐MS FID CRDS HR‐ToF‐AMS AE33 CPC SMPS
Oxidation Flow Reactor simulates atmospheric
photochemistry usinghydroxyl (OH) radicals
13 L flow through system UV185 nm and UV254nm OH exposure of days in
few minutes
SET‐UP (1)
Simone M. Pieber 5
MOTIVATION METHODS RESULTS CONCLUSIONS
June 20, 2018
SET‐UP (2)
Coatedmonolith
8cm
grid size: 2 mm
Al2O3
good mechanical properties
high surface area ‐ porosity
water resistant
Pt
high activity for CO and NMHC oxidation
fair stability against poisoning
H2PtCl6 left overs may prevent poisoning by inorganics
CeO2
high oxygen storage capacity (OSC)
improves dispersion of supported metal: smaller metal clusters, more active centers in metal‐support interface
enhances catalyst’s thermal stability
Simone M. Pieber 6
MOTIVATION METHODS RESULTS CONCLUSIONS
June 20, 2018
SET‐UP (3)
Proton Transfer ReactionMass Spectrometry (PTR‐MS)Jordan et al., 2011
Gas phase organic compoundsProton affinitiy higher than water(good for aromatics, limited for alkanes)Soft ionization, molecular information retained
Aerosol Mass Spectrometry (AMS)Canagaratna et al., 2007
Particulate, sub‐mircon, non‐refractory PMTotal mass informationSpeciation: NO3, NH4, SO4, Chl, OABulk properties ofOA O:C, H:C, etc., mass spectra
Time‐of‐flightMass Analyzer
RESULTS
Simone M. Pieber 8
MOTIVATION METHODS RESULTS CONCLUSIONS
June 20, 2018
before after
Realistic Temperature1.0
0.8
0.6
0.4
0.2
0.0
Rel
ativ
e co
nver
sion
600500400300200100Set Temperature, °C
Pt/Al2O3CH4 (E5)CO (E5)NMHC (E5)
Pt/CeO2-Al2O3
CH4 (E3,7,8,9)CO (E3,7,8,9)NMHC (E3,7,8,9)
8cm
grid size: 2 mm
2 cm
CO, NMHC & METHANE
50%
Significant reduction of CO and NMHC at realistic chimney temperatures (200‐400°C)
CeO2 facilitates methane conversion
Simone M. Pieber 9
MOTIVATION METHODS RESULTS CONCLUSIONS
100
80
60
40
20
0
SOA
Red
uctio
n, %
100806040200
NMHC Reduction, %
Pt/Al2O3 E6
Pt/CeO2-Al2O3
E4 E10
185°C
250°C 310°C
185°C
1:1
310°C200°C
1000
800
600
400
200
0
SOA
form
ed, µ
g m
-3
w/o
cat
.18
5°C
w/o
cat
.18
5°C
250°
C31
0°C
w/o
cat
.20
0°C
310°
C
Pt/CeO2-Al2O3Pt/Al2O3
E6
E4
E10
SOA REDUCTION VS. NMHC
Significant reduction of SOA at realistic chimney temperatures (185‐310°C) SOA reduction exceeds «FID‐based NMHC» reduction by far