Dynamics of an inverse diffusion flame and its role in polycyclic-aromatic-hydrocarbon and soot formation

2005 ◽  
Vol 142 (1-2) ◽  
pp. 33-51 ◽  
Author(s):  
Viswanath R. Katta ◽  
Linda G. Blevins ◽  
William M. Roquemore
Keyword(s):  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Diffusion Flame ◽  
Soot Formation ◽  
Polycyclic Aromatic ◽  
Inverse Diffusion ◽  
Inverse Diffusion Flame

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.

Decomposition of Toluene as a Biomass Tar Through Partial Combustion

2011 ◽  
Author(s):  
Noriaki Nakatsuka ◽  
Yasushi Imoto ◽  
Jun Hayashi ◽  
Miki Taniguchi ◽  
Kenichi Sasauchi ◽  
...  
Keyword(s):  
Power Generation ◽  
Aromatic Hydrocarbons ◽  
Diffusion Flame ◽  
Soot Formation ◽  
Producer Gas ◽  
Carbon Yield ◽  
Hydrogen Addition ◽  
Combustion Region ◽  
Inverse Diffusion ◽  
Inverse Diffusion Flame

For the electric power generation by the woody biomass gasification, tar is incidentally formed at the same time. Tar means a compound of many kinds of aromatic hydrocarbons and causes some troubles, for example, clogging pipes when it is cooled and condensed before being supplied to the gas engine for electric power generation. One way for reducing tar is oxidative and thermal cracking by partial combustion of the producer gas in the gas reformer that is a stage subsequent to the biomass gasifier. During the partial combustion process of the producer gas, inverse diffusion flame is formed when oxidizer is supplied to producer gas. Cracking and polymerization of tar occur simultaneously at the proximity of the inverse diffusion flame. This polymerization of tar into soot is, however, a significant problem in the gas reformer. Experimental study was performed to clarify the effect of hydrogen concentration in the combustion region on soot formation and the growth of polycyclic aromatic hydrocarbons (PAHs) that is precursor of soot. In the present study, hydrogen concentration at the proximity of the inverse diffusion flame was controlled by the small amount of hydrogen addition to the oxidizer. The main results were as follows. Soot formation was suppressed by the small amount of hydrogen addition (approximately 0.5% to the total enthalpy of the producer gas). The suppression of soot formation was caused by higher concentration of hydrogen at the proximity of the combustion region since the aromatic radicals were neutralized before they could combine together or with acetylene. Carbon yield was increased with the increase in the amount of hydrogen added to the oxidizer as carbon content in the undetectable components by the integrated gas chromatograph such as the soot was decreased. In addition, the increase of carbon yield resulted mainly from the increase in carbon monoxide stemmed from reforming of high-boiling components such as soot.

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
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