[email protected] Markus KRAFT [email protected] Markus KRAFT 10 Ogen 2020 Motivation –health...
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Transcript of [email protected] Markus KRAFT [email protected] Markus KRAFT 10 Ogen 2020 Motivation –health...
[email protected] Markus KRAFT 11
[email protected] Markus KRAFT 22
Carbonaceous nanoparticle formation in flames
Jacob Martin, Gustavo Leon, Kimberly Bowal, Angiras Menon, Laura Pascazio, Maurin Salamanca and Markus Kraft
…with contributions from members of the Computational Modelling Group and others
Combustion Webinar | 29th August 2020
[email protected] Markus KRAFT 8
IPCC 2013
Shipmap.org
Motivation – climate change
Internal combustion engines and
furnaces produce black carbon.
Agricultural fires also produce
brown/organic carbon.
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Ogen 2020
Motivation – health impact
• SARS correlation with air pollution
index in China (Cui et al. 2003)
• Preprint from Harvard shows 1 μg/m3
in PM2.5 is associated with an 2-15%
increase in COVID-19 death rate? (Wu
et al. medRxiv 2020)
• Particulates as carrier of the virus? As
with influenza and measles (Setti et al.
2020)
• Is it due to copollutant NOx?
(Ogen 2020, Martelletti et al. 2020)
PM10
NOx
Wu et al. medRxiv 2020
Martelletti et
al. 2020
From 66 administrative regions in Italy,
Spain, France and Germany, 78% of
COVID-19 deaths occurred in the five
most polluted regions. (Ogen 2020)
[email protected] Markus KRAFT 13
Lavvas, P., Sander, M., Kraft, M., & Imanaka, H. (2011).
Surface chemistry and particle shape: processes for the
evolution of aerosols in Titan's atmosphere. The
Astrophysical Journal, 728(2), 80.
Space, the final frontier…
Ames Research Centre
NASA
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Carbon black... ApplicationsPigment blacks
• Used for printing inks – particle size and surface determine colour and viscosity
• The coating sector uses jet black – oxidised, fine particles
• Plastic industry – fine particles for UV resistance and for anti-static, e.g. power cables, carbon brushes and electrodes
• Paper industry – medium size particles – decoration
• Construction industry – coarse particles
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Reinforcing and rubber blacks
• Discovered by accident in the 19th
century• Replaced zinc oxide• Eliminates the stickiness of rubber
• Active blacks• E.g. tires – size: 20 nm
• Semi-active • E.g. floor mats – size: 50 nm
• Characterised by size, surface area and after treatment
• More than 90% of carbon black for the rubber industry
Carbon black... Applications
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Shipmap.org
“A major breakthrough in understanding carbon
[soot] formation will have been achieved when it
becomes possible in at least one case to account
for the entire course of nucleation and growth
of carbon on the basis of a fundamental
knowledge of reaction rates and mechanisms”
Palmer and Cullis, 1965
Problem statement
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Shipmap.org
Dark zone
Nanoparticles
• PIMS, Half-mini DMA, Nano-SMPS
(Grotheer, Wang, D’Anna, Biswas)
• SAXS, WAXS (di Saito)
• AFM (D’Anna, Minutolo, Wang)
• LII (Michelsen, Desgroux)
• Helium ion microscopy (Wang,
Kohse-Hohinghaus)
• In-situ TEM; oxidation (Thompson,
Toth), nanoindentation (Biswas,
Dassenoy)
Polycyclic aromatic hydrocarbon
• HRTEM (vander Wals, Kraft,
Niessner, Mathews).
• Time resolved LIF, Band gap,
Raman , micro-FT-IR (Desgroux,
Miller, D’Alessio, D’Anna,
Thompson, Minutolo, Wang)
• HR-AFM (IBM, Wornat, D’Anna)
STM (Thürmer)
• Tunable PI-MS, i2PEPICO (Fei Qi,
Michelsen, Hansen, Desgroux)
atmospheric (Carbone) HR-MS
(Miller, Sarathy), SI-MS (Desgroux,
Focsa)Courtesy of J. W. Martin
[email protected] Markus KRAFT 1919
Shipmap.org
Sooting propensity of fuels
Smoke point lamp (ASTM D1322)
An improved methodology for
determining threshold sooting
indices from smoke point
lamps
Roger Watson, Maria Botero,
Christopher Ness, Neal M.
Morgan, and Markus Kraft,
Fuel 111, 120-130, (2013).
Reproduced and extended by
researchers at Aachen 2018
FURTI: Fuel
uptake rate
measurement
with
threshold
[email protected] Markus KRAFT 20
Sooting propensity of fuels Yale co-flow diffusion
doped-heptane flame
Yield sooting index (YSI) doped
methane diffusion flame. Provides
comprehensive unified scale.
(McEnally, Pfefferle et al. 2018)
FLiPPID for
Inverse Abel
transform from
colour ratio
pyrometry (Dreyer,
Kraft et al. 2019).
https://como.ceb.cam.ac.uk/resources/flpyro/
Colour ratio pyrometry
Improved methodology for performing the inverse Abel transform of flame images for color ratio
pyrometry Jochen Dreyer, Radomir I. Slavchov, Eric J. Rees, Jethro Akroyd, Maurin Salamanca,
Sebastian Mosbach, and Markus Kraft, Applied Optics 58(10), 2662-2670, (2019).
[email protected] Markus KRAFT 22
Stochastic Particle Method (SPM)- Type space
Binary tree
Aggregates are formed by primary particles that are formed by molecules (PAHs).
𝐂 =
0 ⋯ 0⋮ ⋱ ⋮𝑐𝑖𝑗 ⋯ 0
Adjacency matrix
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SPM - Type space
𝑝𝑖 = 𝑝𝑖 𝑚1, … ,𝑚𝑛m 𝑝𝑖 , 𝑟𝑖 , 𝐱𝑖Primary particle
𝑟𝑖 → primary radius
𝐱𝑖 → primary coordinates
Molecule (PAH)
Composed of
𝑛c 𝑚𝑗 carbon atoms,
𝑛s 𝑚𝑗 sites &
Edge connectivity matrix 𝐄 𝑚𝑗
Atom (Carbon)
𝑚𝑗 = 𝑚𝑗 𝑐1, … , 𝑐𝑛c 𝑚𝑗, 𝑠1, … , 𝑠𝑛s 𝑚𝑗
, 𝐄 𝑚𝑗
𝑐𝑘 = 𝑐𝑘 𝑥𝑘 , 𝑎𝑘 , 𝛿𝑘,Edge𝑥𝑘 → atom coordinates𝑎𝑘 → heteroatom type (H, O, …)
𝛿𝑘,Edge ቊ1,0,
for edge atomsotherwise
(where reactions happen)
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SPM - Type space
The model is based on reactive sites, each with specific reaction rates.
𝑠𝛼 = 𝑠𝛼 𝑐𝑘first , 𝑐𝑘last , 𝜂
𝑐𝑘first , 𝑐𝑘last→ first and last carbon atoms of a site
typically where reaction starts (H abstraction)𝜂→ site type
Site
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SPM - Particle evolution
Numerical simulations of soot aggregation in
premixed laminar flames
Neal M. Morgan, Markus Kraft, Michael
Balthasar, David Wong, Michael Frenklach,
and Pablo Mitchell, Proceedings of the
Combustion Institute 31(1), 693-700, (2007).
Simulation of primary particle size distributions in a
premixed ethylene stagnation flame
Dingyu Hou, Casper Lindberg, Mengda Wang,
Manoel Y. Manuputty, Xiaoqing You, and Markus
Kraft, Combustion and Flame 216, 126-135, (2020).
[email protected] Markus KRAFT 26
SPM - Particle evolution
• The interaction energy between two spherical particles was derived from the L-J potentials of the constituent atoms of the two particles.
• A coagulation efficiency model for soot was proposed based on the interaction energy between the colliding partners and their kinetic energy.
On the coagulation efficiency of carbonaceous nanoparticles
Dingyu Hou, Diyuan Zong, Casper Lindberg, Markus Kraft, and Xiaoqing You, Journal of
Aerosol Science 140, 105478, (2019).
[email protected] Markus KRAFT 27
SPM - Aromatic site modelling
Soot
island
Soot
island
<---> highly reversible reactions(partial equilibrium)
→ forward reaction faster than reverse (steady state)
Leon, Gustavo, et al. "A new methodology to calculate process rates
in a kinetic Monte Carlo model of PAH growth." Combustion and
Flame 209 (2019): 133-143.
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SPM - Aromatic site modellingPAH with 5 carbons and pentagons observed
by the HR-AFM [Commodo et al. 2019]
A density functional theory study on the kinetics of seven-member ring formation in polyaromatic hydrocarbons
Angiras Menon, Gustavo Leon, Jethro Akroyd, and Markus Kraft, Combustion and Flame 217, 152-174, (2020).
PAH with partially embedded
five-membered rings can
integrate heptagons.
[email protected] Markus KRAFT 29
Shipmap.org
Comparison with experiments
S. A. Skeen, H. A. Michelsen, K.
R. Wilson, D. M. Popolan, A.
Violi, and N. Hansen. J. Aerosol
Sci., 58:86–102, 2013.
Kinetic Monte Carlo statistics of curvature integration by HACA growth and bay closure reactions for PAH growth
in a counterflow diffusion flame, Gustavo Leon, Angiras Menon, Laura Pascazio, Eric J. Bringley, Jethro Akroyd,
and Markus Kraft, Technical Report 253, c4e-Preprint Series, Cambridge, 2019. (Accepted in Proceedings of the
Combustion Institute)
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Shipmap.org
Bockhorn, D’Anna, Sarofim, Wang, eds., Combustion Generated
Fine Carbonaceous Particles, Karlsruhe University Press, 2009.
Physical
Chemical
Nanoparticle formation?
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Totton et al. Chem. Phys. Lett. 510, (1-3),
154-160, (2011)
Totton et al. J. Phys. Chem. A 115,
13684–13693, (2011)
Totton et al. J. Chem. The. and Comp. 6,
(3), 683-695, (2010)
Pascazio, Laura, Mariano
Sirignano, and Andrea
D'Anna. "Simulating the
morphology of clusters of
polycyclic aromatic
hydrocarbons: The influence
of the intermolecular
potential." Combustion and
Flame 185 (2017): 53-62.
Wang, Chen S., et al. "Revealing the molecular structure of soot
precursors." Carbon 129 (2018): 537-542.
PAH interactions
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Grotheer 2009
PAH structure analysis of soot in a non-premixed
flame using High-Resolution Transmission
Electron Microscopy and Optical Band Gap
Analysis
Maria Botero, Erin M. Adkins, Silvia Gonzalez
Calera, Houston Miller, and Markus Kraft,
Combustion and Flame 164, 250-258, (2016).
PAH interactions
PAH cannot cluster with physical interactions.
A quantitative study of the clustering of polycyclic
aromatic hydrocarbons at high temperatures
Tim Totton, Alston J. Misquitta, and Markus Kraft,
Physical Chemistry Chemical Physics 14, 4081-4096,
(2012).
[email protected] Markus KRAFT 33
REMD - simulation set upThe following PAH clusters were considered: circumcoronene (CIR) / coronene (COR) and ovalene (OVA) /
pyrene (PYR), each in ratios of 16 / 16 and 50 / 50.
Simulations were initiated in four non-equilibrium configurations: (a) randomly mixed, (b) janus, and (c,d) two
core-shell structures.
A position potential (Epos) was applied to restrain all atoms to a spherical volume to prevent evaporation.
Partitioning of polycyclic aromatic hydrocarbons in heterogeneous clusters
Kimberly L. Bowal, Jacob W. Martin, and Markus Kraft, Carbon 143, 247-256, (2019).
[email protected] Markus KRAFT 34
REMD videos
Low temperature replica (400K) High temperature replica (1500K)
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Results - Large cluster snapshots
Final configurations of large clusters containing 100 molecules (left:
CIR, COR; right: OVA, PYR) show same stacked structure and size
partitioning
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REMD radial distance vs time
Average radial
distance of each
molecule type
Radial distances
over time show
partitioning in low
energy replicas and
mixing in high
energy replicas
[email protected] Markus KRAFT 37
Internal nanostructure – core-shell
To date, molecular modelling studies represent soot particles as homogeneous PAH
clusters.
Internal structure of soot particles in a diffusion flame
Maria Botero, Yuan Sheng, Jethro Akroyd, Jacob W. Martin, Jochen Dreyer, Wenming Yang, and Markus Kraft,
Carbon 141, 635-642, (2019).
[email protected] Markus KRAFT 38
Sphere Encapsulated Monte Carlo Obtaining minimum energy configurations of large aromatic systems
• Sphere Encapsulated Monte Carlo method is developed to overcome
ring interlocking
• Minimum energy configurations are determined at low computational
expense
• Applied to clusters beyond the scope of existing methods
Sphere Encapsulated
Monte Carlo: Obtaining
Minimum Energy
Configurations of Large
Aromatic Systems
Kimberly L. Bowal, Peter
Grancic, Jacob W.
Martin, and Markus Kraft,
Journal of Physical
Chemistry A 123(33),
7303-7313, (2019).
[email protected] Markus KRAFT 39
Evaluation of complex PAH clusters
More complex systems were
considered to further illustrate the
potential of the SEMC method:
clusters containing nine different
molecule types (a-c) and a cluster
containing 150 molecules of three
different molecule types (d).
[email protected] Markus KRAFT 40
• Reduction in soot seen
when an electric field is
applied to a flame.
• Hypothesis: electric
fields increase the
charge concentration in
the flame seeding many
more smaller soot
particles which are
easily combusted or
removed by the e-field.
Weinberg 1969
E-field on
E-field off air
ethylene
air
ethylene
[email protected] Markus KRAFT 41
B97D/cc-pVTZ
PAH interactions
Flexoelectricity and the Formation of Carbon
Nanoparticles in Flames, Jacob W. Martin, Maria
Botero, Radomir I. Slavchov, Kimberly L. Bowal,
Jethro Akroyd, Sebastian Mosbach, and Markus Kraft,
The Journal of Physical Chemistry C 122(38), 22210-
22215, (2018).
Polar curved polycyclic aromatic hydrocarbons in soot
formation, Jacob W. Martin, Kimberly L. Bowal, Angiras
Menon, Radomir I. Slavchov, Jethro Akroyd, Sebastian
Mosbach, and Markus Kraft, Proceedings of the
Combustion Institute 37(1), 1117-1123, (2019).
[email protected] Markus KRAFT 42
curPAHIPIon-Induced Soot Nucleation Using a New Potential for Curved Aromatics
Kimberly L. Bowal, Jacob W. Martin, Alston J. Misquitta, and Markus Kraft,
Combustion Science and Technology 191(5-6), 747-765, (2019).
[email protected] Markus KRAFT 43
Molecular dynamics
• Large system using molecular dynamics
• 1000 corannulenemolecules
• curPAHIP force field
• With and without K+
• 500, 750, 1000,1500 K
K+
[email protected] Markus KRAFT 44
[email protected] Markus KRAFT 45
Nanoindentation experiments
P
Material Hardness (GPa)
Nanocrystalline graphite 0.1-0.4
HOPG 2.4
Carbon black 3-4
Ethylene soot [1] 3-5
Charcoal 3-5
Diesel Soot [2] 6-7
Glassy carbon 30
Diamond 100
[1] Bhowmick et al., Tribol Lett (2011) 44:139–149
[2] Bhowmick et al., Proc. IMechE Part C: J. Mechanical Engineering Science, 226: 394-402
[email protected] Markus KRAFT 46
Nanoindentation experiment
[1] Jenei et al., Nanotechnology 29 (2018) 085703
[2] Jenei et al., Tribology International 131 (2019) 446–453
[email protected] Markus KRAFT 47
NanoindentationSimulation parameters:NPT ensemble𝑇 = 300 K𝑃 = 1 atmΔ𝑡 = 0.5 fs
Planar indentervindenter = 25 m/shmax = 0.6 Dparticle
AIREBO-M potentialLAMMPS P
𝑯𝒂𝒓𝒅𝒏𝒆𝒔𝒔 𝑯 =𝑃𝑚𝑎𝑥
𝐴
𝒀𝒐𝒖𝒏𝒈′𝒔 𝒎𝒐𝒅𝒖𝒍𝒖𝒔 𝑬 = 𝑓(𝑆, 𝜈)
𝑃𝑚𝑎𝑥 = 𝑚𝑎𝑥𝑖𝑚𝑢𝑚 𝑙𝑜𝑎𝑑𝐴 = 𝑐𝑜𝑛𝑡𝑎𝑐𝑡 𝑎𝑟𝑒𝑎𝑆 = 𝑚𝑎𝑥𝑖𝑚𝑢𝑚 𝑠𝑙𝑜𝑝𝑒 𝑜𝑓𝑡ℎ𝑒 𝑢𝑛𝑙𝑜𝑎𝑑𝑖𝑛𝑔 𝑐𝑢𝑟𝑣𝑒ν = 𝑃𝑜𝑖𝑠𝑠𝑜𝑛′𝑠 𝑟𝑎𝑡𝑖𝑜
S
LOADUNLOAD
Exploring the internal structure of soot particles using nanoindentation: A
reactive molecular dynamics study
Laura Pascazio, Jacob W. Martin, Kimberly L. Bowal, Jethro Akroyd, and
Markus Kraft, Combustion and Flame 219, 45-56, (2020).
[email protected] Markus KRAFT 48
Internal nanostructure – core-shell
To date, molecular modelling studies represent soot particles as homogeneous PAH
clusters.
Internal structure of soot particles in a diffusion flame
Maria Botero, Yuan Sheng, Jethro Akroyd, Jacob W. Martin, Jochen Dreyer, Wenming Yang, and Markus Kraft,
Carbon 141, 635-642, (2019).
[email protected] Markus KRAFT 49
Starting configurations
Rcore
x
dshell
CIRCUMANTHRACENE
CORONENE
CL =2 ∙ ncrosslinksnmolecules
CL = 1
CL = 2
CL > 2
Rp,dshell𝑅𝑐ore
, CLcore, CLshell
Rp
[email protected] Markus KRAFT 50
PACKING MOLECULES
Starting configurations
COMBINE CORE-SHELL
Simulation parameters:NVT ensemble𝑇 = 1000 KΔ𝑡 = 0.25 fs
AIREBO-M potentialLAMMPS
CROSSLINKING MD
ρparticle = 1.5g
cm3
[email protected] Markus KRAFT 51
Starting configurations
PACKING MOLECULES
CROSSLINKING MD
COMBINE CORE-SHELL
[1] Jenei et al., Nanotechnology 29 (2018) 085703
HRTEM [1]simulated TEM
5 nm
core shell
core
shell
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Results – Only core particles
0.6 Dp
dis
pla
ce
ment
timet1 t2 t3
Rcore = 3.5 nm
t = 0 t = t1 t = t3
CL
= 0
CL
= 2
CL
= 3
.5
𝑧𝑖
𝑧𝑓
Sq
ua
sh
rati
o
[email protected] Markus KRAFT 53
Results – Only core particles
[1] Bhowmick et al., Tribol Lett (2011)
44:139–149
[2] Bhowmick et al., Proc. IMechE
Part C: J. Mechanical Engineering
Science, 226: 394-402
[3] Jenei et al., Nanotechnology 29
(2018) 085703
• H very low when CL < 1.5• H increase with CL• H does not depend on• the particle size
Soot[1],[2],[3]
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Shipmap.org
Evidence for reactive edges, crosslinking and partial saturation
D’Anna Group
Commodo et al. 2019
[email protected] Markus KRAFT 55
Shipmap.org
Mechanism comparison
Reactivity of Polycyclic Aromatic Hydrocarbon Soot Precursors: Implications of Localized π-Radicals on Rim-Based
Pentagonal Rings, Jacob W. Martin, Dingyu Hou, Angiras Menon, Laura Pascazio, Jethro Akroyd, Xiaoqing You, and
Markus Kraft, The Journal of Physical Chemistry C 123(43), 26673-26682, (2019).
[email protected] Markus KRAFT 56
Shipmap.org
Physical + Chemical
“Once coagulated they will quickly become chemically knit together
since a significant fraction of the aromatic species are radicals”
Harris and Weiner, 1989
“..if individual PAH or their dimers undergo rapid, irreversible
reactions, the net rate of production of the soot nuclei may be
sufficiently high so that the concentration of the nuclei far exceeds
the concentrations of the reacting, intermediate species.”
Miller, 1991
“…the mass flux is likely to be driven by an irreversible process
following the dimer formation...It is also possible that a PAH dimer is
stabilized by a reaction with an aliphatic, forming a covalently bonded
link between the PAH layers... the van der Waals enhancement
should be larger than the factor of 2.2 assumed in the present study.”
Frenklach and Wang, 1991
[email protected] Markus KRAFT 57
Binding energy
-110
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
0 100 200 300 400 500
bin
din
g e
nerg
y (
kca
l/m
ol)
Molecular mass (Da)
localised 𝜋-radical B) +
rim pentagon E)
ΔE= 8±4 kcal/mol
RSR C)
ΔE = 6±3 kcal/mol
localised 𝜋-radical B)
ΔE = 50±3 kcal/mol
c) non-bonded + stack - ____
SAPT(DFT) Totton et al.
M06-2X-D3/cc-pVTZ
d) bond + stack -________
B97D overpredicts
dispersion interactions by
− 6 ± 1 kcal/mol so we will
compare any covalent
bond with enhancement
with the non-bonded
calculations.
RSR can provide some
small increase in binding
energy
Localised 𝜋-radicals can
stack and bond strongly
localised 𝜋-radical B) +
partially embedded
pentagon D)
ΔE = 35±6 kcal/mol
Rotating
single bonds
a) bond b) bond + stack
Reactivity of Polycyclic Aromatic Hydrocarbon Soot Precursors: Implications of Localized π-Radicals on Rim-Based Pentagonal Rings
Jacob W. Martin, Dingyu Hou, Angiras Menon, Laura Pascazio, Jethro Akroyd, Xiaoqing You, and Markus Kraft, The Journal of Physical
Chemistry C 123(43), 26673-26682, (2019).
[email protected] Markus KRAFT 58
Localised vs. non-localised π-radicals
Spin density
does not
spread out
Radical is
localised
due to
aromaticity
Spin density
spreads out
Radical is
delocalised due
to aromaticity
Reactive localized π-radicals on rim-based pentagonal rings: properties and concentration in flames
Angiras Menon, Jacob W. Martin, Gustavo Leon, Dingyu Hou, Laura Pascazio, Xiaoqing You, and Markus Kraft,
Proceedings of the Combustion Institute, 2020, In Press
[email protected] Markus KRAFT 59
Concentration of localised π-radicals
27
12
4
SPM - KMC
Schulz, Fabian, et al. "Insights into incipient
soot formation by atomic force
microscopy." Proceedings of the Combustion
Institute 37.1 (2019): 885-892.
Reactive localized π-radicals on rim-based pentagonal rings: properties and concentration in flames
Angiras Menon, Jacob W. Martin, Gustavo Leon, Dingyu Hou, Laura Pascazio, Xiaoqing You, and Markus Kraft,
Proceedings of the Combustion Institute, 2020, In Press
HR-AFM
Time (s)
Mole
Fra
ction
[email protected] Markus KRAFT 60
Shipmap.org
The Middle Way
Physical/Electrical
+ Chemical
Martin, Jacob. Investigating the role of curvature on the formation and
thermal transformations of soot. Diss. University of Cambridge, 2020.
Molecular weight
[email protected] Markus KRAFT 61
Shipmap.org
JacobMartin,. Investigating the role of
curvature on the formation and thermal
transformations of soot. Diss. University of
Cambridge, 2020.
[email protected] Markus KRAFT 62
This project is funded by the National Research Foundation (NRF),
Prime Minister's Office, Singapore under its Campus for Research Excellence and Technological Enterprise
(CREATE) programme.
