scholarly journals Laboratory analogs of carbonaceous matter: Soot and its precursors and by-products

2008 ◽  
Vol 4 (S251) ◽  
pp. 425-432 ◽  
Author(s):  
Cornelia Jäger ◽  
Harald Mutschke ◽  
Isabel Llamas-Jansa ◽  
Thomas Henning ◽  
Friedrich Huisken
Keyword(s):  
Aromatic Hydrocarbons ◽  
Soot Formation ◽  
Formation Mechanisms ◽  
Carbonaceous Matter ◽  
Condensed Carbon ◽  
End Products ◽  
Polycyclic Aromatic ◽  
Experimental Findings ◽  
By Products ◽  
Reactive Gas

AbstractCarbonaceous materials have been prepared in the laboratory by laser-induced pyrolysis of a mixture of hydrocarbons under different conditions and laser ablation of graphite in reactive gas atmospheres. We have investigated the soluble and insoluble parts of the condensed carbon powders with several spectroscopic and chromatographic methods in order to obtain information on the composition of the condensate. The results of these experiments have demonstrated that, at temperatures lower than 1700 K, the pyrolysis by-products are mainly PAHs, whereas at higher temperatures fullerenes and polyyne-based compounds are formed. The experimental findings point to different soot formation mechanisms with variable intermediates and end products. It has been found that soot extracts can contain more than 65 different polycyclic aromatic hydrocarbons (PAHs). Eventually, the study of the condensation pathways of soot particles and their precursors and by-products will permit the prediction of the spectral properties of carbonaceous matter in space.

scholarly journals Dimers of polycyclic aromatic hydrocarbons: the missing pieces in the soot formation process

2019 ◽  
Vol 21 (16) ◽  
pp. 8282-8294 ◽  
Author(s):  
X. Mercier ◽  
O. Carrivain ◽  
C. Irimiea ◽  
A. Faccinetto ◽  
E. Therssen
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Experimental Evidence ◽  
Aromatic Hydrocarbons ◽  
Diffusion Flame ◽  
Formation Process ◽  
Soot Formation ◽  
Laminar Diffusion Flame ◽  
Laminar Diffusion ◽  
Polycyclic Aromatic

Experimental evidence supporting the existence of PAH dimers in the proximity of the soot nucleation region of a methane laminar diffusion flame.

Formation mechanisms of soot from high-molecular-weight polycyclic aromatic hydrocarbons

2015 ◽  
Vol 162 (6) ◽  
pp. 2670-2678 ◽  
Author(s):  
Kiminori Ono ◽  
Yoshiya Matsukawa ◽  
Kazuki Dewa ◽  
Aki Watanabe ◽  
Kaname Takahashi ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Polycyclic Aromatic Hydrocarbons ◽  
High Molecular Weight ◽  
Aromatic Hydrocarbons ◽  
Formation Mechanisms ◽  
Polycyclic Aromatic

scholarly journals Bioremediation of Heavy Metals and Organic Toxicants by Composting

2002 ◽  
Vol 2 ◽  
pp. 407-420 ◽  
Author(s):  
Allen V. Barker ◽  
Gretchen M. Bryson
Keyword(s):  
Organic Matter ◽  
Aromatic Hydrocarbons ◽  
Organic Contaminants ◽  
Contaminated Soils ◽  
Native Plants ◽  
Organic Complexes ◽  
Soils And Sediments ◽  
Polycyclic Aromatic ◽  
By Products ◽  
Metallic Pollutants

Hazardous organic and metallic residues or by-products can enter into plants, soils, and sediments from processes associated with domestic, municipal, agricultural, industrial, and military activities. Handling, ingestion, application to land or other distributions of the contaminated materials into the environment might render harm to humans, livestock, wildlife, crops, or native plants. Considerable remediation of the hazardous wastes or contaminated plants, soils, and sediments can be accomplished by composting. High microbial diversity and activity during composting, due to the abundance of substrates in feedstocks, promotes degradation of xenobiotic organic compounds, such as pesticides, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs). For composting of contaminated soils, noncontaminated organic matter should be cocomposted with the soils. Metallic pollutants are not degraded during composting but may be converted into organic combinations that have less bioavailability than mineral combinations of the metals. Degradation of organic contaminants in soils is facilitated by addition of composted or raw organic matter, thereby increasing the substrate levels for cometabolism of the contaminants. Similar to the composting of soils in vessels or piles, the on-site addition of organic matter to soils (sheet composting) accelerates degradation of organic pollutants and binds metallic pollutants. Recalcitrant materials, such as organochlorines, may not undergo degradation in composts or in soils, and the effects of forming organic complexes with metallic pollutants may be nonpermanent or short lived. The general conclusion is, however, that composting degrades or binds pollutants to innocuous levels or into innocuous compounds in the finished product.

scholarly journals Polycyclic aromatic hydrocarbons (PAHs) and soot formation in the pyrolysis of the butanol isomers

Fuel ◽  
2017 ◽  
Vol 197 ◽  
pp. 348-358 ◽  
Author(s):  
F. Viteri ◽  
S. Gracia ◽  
Á. Millera ◽  
R. Bilbao ◽  
M.U. Alzueta
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Soot Formation ◽  
Polycyclic Aromatic

Polycyclic Aromatic Hydrocarbons and Soot Emissions in Oxygenated Ethylene Diffusion Flames at Elevated Pressures

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Krishna C. Kalvakala ◽  
Suresh K. Aggarwal
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Volume Fraction ◽  
Diffusion Flames ◽  
Soot Formation ◽  
Computational Study ◽  
Flame Temperature ◽  
Elevated Pressures ◽  
Polycyclic Aromatic ◽  
Soot Emissions

We report herein a computational study to characterize the effect of oxygenation on polycyclic aromatic hydrocarbons (PAHs) and soot emissions in ethylene diffusion flames at pressures 1–8 atm. Laminar oxygenated flames are established in a counterflow configuration by using N2 diluted fuel stream along with O2-enriched oxidizer stream such that the stoichiometric mixture fraction (ζst) is varied, but the adiabatic flame temperature is not materially changed. Simulations are performed using a validated fuel chemistry model and a detailed soot model. The primary objective is to enhance the fundamental understanding of PAHs and soot formation in oxygenated flames at elevated pressures. At a given pressure, as the level of oxygenation (ζst) is increased, we observe a significant reduction in PAHs (benzene and pyrene) and consequently in soot formation. On the other hand, at a fixed ζst, as pressure is increased, it leads to increased PAHs formation and thus higher soot emission. Both soot number density and soot volume fraction increase with pressure. The reaction path analysis indicates that at higher pressures, the C2/C4 path becomes more significant for benzene formation compared to the propargyl recombination path. Results further indicate that the effectiveness of oxygenation in reducing the formation of pyrene and soot becomes less pronounced at higher pressures. In contrast, the effect of pressure on pyrene and soot formation becomes more pronounced at higher oxygenation levels. The behavior can be explained by examining the flame structure and hydrodynamics effects at different pressure and oxygenation levels.

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