Laser microprobe analysis of soot precursor particles and carbonaceous soot

Conference · Sun Jan 01 04:00:00 EST 1995 · Combustion and Flame; (United States)

OSTI ID:6556488

Dobbins, R A; Lu, W ^[1]; Fletcher, R A ^[2]

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1. Brown Univ., Providence, RI (United States). Div. of Engineering
2. National Inst. of Standards and Technology, Gaithersburg, MD (United States). Chemical Science and Technology Lab.

Samples of soot precursor particles and carbonaceous soot from a nonsmoking ethene diffusion flame have been analyzed by means of laser microprobe mass spectrometry (LMMS). The mass spectra of soot precursor particles from the lower flame display many peaks in the 200--300-amu range that are characteristic of polycyclic aromatic hydrocarbons (PAHs). The most prominent of these are the masses 252, 276, and 300, which correspond to the isomers of C[sub 20]H[sub 12], C[sub 22]H[sub 12], and C[sub 24]H[sub 12], respectively. These masses are among those predicted by Stein and Fahr to be the most thermodynamically stable (stabilomers) under typical hydrocarbon flame conditions, and they have been previously reported as components of soot collected from a variety of fuels and combustion configurations. Carbonaceous soot from the upper region of the flame yields mass spectra composed of carbon-hydrogen clusters, C[sub x]H[sub y] with x = 3 to 24 and y usually 0, 1, or 2. Smaller amounts of PAH-like species with masses in the 418 to 444 amu range are also found. These results suggest that the carbonization process observed in this flame is the dehydrogenation of the PAH species formed in the lower flame unaccompanied by polymeric growth. The LMMS technique provides a lower bound value of the hydrogen mole fraction X[sub H] of 0.36 (C/H = 1.8) for precursor particles from the lower diffusion flame and 0.15 (C/H = 5.6) for carbonaceous soot aggregates.

• OSTI ID: 6556488
• Report Number(s): CONF-940711--
• Conference Information: Journal Name: Combustion and Flame; (United States) Journal Volume: 100:1-2
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020800 -- Petroleum-- Waste Management
025000* -- Petroleum-- Combustion
ALKENES
AROMATICS
CHEMICAL REACTION KINETICS
COALESCENCE
COMBUSTION KINETICS
ETHYLENE
HYDROCARBONS
KINETICS
MASS SPECTROSCOPY
ORGANIC COMPOUNDS
POLYCYCLIC AROMATIC HYDROCARBONS
PRECURSOR
REACTION KINETICS
SOOT
SPECTROSCOPY