Reactive polycyclic aromatic hydrocarbon dimerization drives soot nucleation

2018 ◽  
Vol 20 (16) ◽  
pp. 10926-10938 ◽  
Author(s):  
M. R. Kholghy ◽  
G. A. Kelesidis ◽  
S. E. Pratsinis
Keyword(s):  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
High Temperatures ◽  
Soot Formation ◽  
Chemical Bonds ◽  
Polycyclic Aromatic ◽  
Negligible Contribution

Nucleation is an important yet poorly understood step in soot formation. Strong chemical bonds between PAH monomers are required as physical dimerization cannot explain soot formation at high temperatures. Dimers can be considered as soot nuclei as larger oligomers have negligible contribution.

Modeling Soot Formation Using Reduced Polycyclic Aromatic Hydrocarbon Chemistry in n-Heptane Lifted Flames With Application to Low Temperature Combustion

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Gokul Vishwanathan ◽  
Rolf D. Reitz
Keyword(s):  
Low Temperature ◽  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Internal Combustion Engines ◽  
Soot Formation ◽  
Numerical Study ◽  
Low Temperature Combustion ◽  
Temperature Combustion ◽  
Lifted Flames ◽  
Polycyclic Aromatic

A numerical study of in-cylinder soot formation and oxidation processes in n-heptane lifted flames using various soot inception species has been conducted. In a recent study by the authors, it was found that the soot formation and growth regions in lifted flames were not adequately represented by using acetylene alone as the soot inception species. Comparisons with a conceptual model and available experimental data suggested that the location of soot formation regions could be better represented if polycyclic aromatic hydrocarbon (PAH) species were considered as alternatives to acetylene for soot formation processes. Since the local temperatures are much lower under low temperature combustion conditions, it is believed that significant soot mass contribution can be attributed to PAH rather than to acetylene. To quantify and validate the above observations, a reduced n-heptane chemistry mechanism has been extended to include PAH species up to four fused aromatic rings (pyrene). The resulting chemistry mechanism was integrated into the multidimensional computational fluid dynamics code KIVA-CHEMKIN for modeling soot formation in lifted flames in a constant volume chamber. The investigation revealed that a simpler model that only considers up to phenanthrene (three fused rings) as the soot inception species has good possibilities for better soot location predictions. The present work highlights and illustrates the various research challenges toward accurate qualitative and quantitative predictions of the soot for new low emission combustion strategies for internal combustion engines.

Polycyclic Aromatic Hydrocarbon (PAH) and Soot Formation in the Pyrolysis of Acetylene and Ethylene: Effect of the Reaction Temperature

2012 ◽  
Vol 26 (8) ◽  
pp. 4823-4829 ◽  
Author(s):  
Nazly E. Sánchez ◽  
Alicia Callejas ◽  
Ángela Millera ◽  
Rafael Bilbao ◽  
María U. Alzueta
Keyword(s):  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Reaction Temperature ◽  
Soot Formation ◽  
Polycyclic Aromatic

1,1’-Biaceanthrylene and 2,2'-Biaceanthrylene: Models for Linking Larger Polycyclic Aromatic Hydrocarbons via Five-Membered Rings

2019 ◽  
Author(s):  
Yachu Du ◽  
Kyle Plunkett
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Electronic Properties ◽  
Aromatic Hydrocarbons ◽  
Model Systems ◽  
Redox Potentials ◽  
Dimer Model ◽  
Optical And Electronic Properties ◽  
Polycyclic Aromatic

We show that polycyclic aromatic hydrocarbon (PAH) chromophores that are linked between two five-membered rings can access planarized structures with reduced optical gaps and redox potentials. Two aceanthrylene chromophores were connected into dimer model systems with the chromophores either projected outward (2,2’-biaceanthrylene) or inward (1,1’-biaceanthrylene) and the optical and electronic properties were compared. Only the planar 2,2’-biaceanthrylene system showed significant reductions of the optical gaps (1 eV) and redox potentials in relation to the aceanthrylene monomer.<br>

1,1’-Biaceanthrylene and 2,2'-Biaceanthrylene: Models for Linking Larger Polycyclic Aromatic Hydrocarbons via Five-Membered Rings

2019 ◽  
Author(s):  
Yachu Du ◽  
Kyle Plunkett
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Electronic Properties ◽  
Aromatic Hydrocarbons ◽  
Model Systems ◽  
Redox Potentials ◽  
Dimer Model ◽  
Optical And Electronic Properties ◽  
Polycyclic Aromatic

We show that polycyclic aromatic hydrocarbon (PAH) chromophores that are linked between two five-membered rings can access planarized structures with reduced optical gaps and redox potentials. Two aceanthrylene chromophores were connected into dimer model systems with the chromophores either projected outward (2,2’-biaceanthrylene) or inward (1,1’-biaceanthrylene) and the optical and electronic properties were compared. Only the planar 2,2’-biaceanthrylene system showed significant reductions of the optical gaps (1 eV) and redox potentials in relation to the aceanthrylene monomer.<br>

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