Determination of kinetic data for soot oxidation: Modeling of competition between oxygen diffusion and reaction during thermogravimetric analysis

Journal Article · Fri Oct 01 00:00:00 EDT 1993 · Combustion and Flame; (United States)

DOI:https://doi.org/10.1016/0010-2180(93)90054-7· OSTI ID:5575019

Gilot, P; Bonnefoy, F; Marcuccilli, F; Prado, G ^[1]

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1. Ecole Nationale Superieure de Chimie de Mulhouse, Mulhouse (France). Lab. Gestion des Risques et Environnement

Kinetic data concerning carbon black oxidation in the temperature range between 600 and 900 C have been obtained using thermogravimetric analysis. Modeling of diffusion in a boundary layer above the pan and inside the porous medium coupled to oxygen reaction with carbon black is necessary to obtain kinetic constants as a function of temperature. These calculations require the knowledge of the oxidation rate at a given constant temperature as a function of the initial mass loading m[sub o]. This oxidation rate, expressed in milligrams of soot consumed per second and per milligram of initial soot loading, decreases when m[sub o] increases, in agreement with a reaction in an intermediary regime where the kinetics and the oxygen diffusion operate. The equivalent diffusivity of oxygen inside the porous medium is evaluated assuming two degrees of porosity: between soot aggregates and inside each aggregate. Below 700 C an activation energy of about 103 kJ/mol can be related to a combustion reaction probably kinetically controlled. Beyond 700 C the activation energy of about 20 kJ/ mol corresponds to a reaction essentially controlled by oxygen diffusion leading to a constant density oxidation with oxygen consumption at or near the particle surface. To validate these data, they are used in the modeling of a Diesel particulate trap regeneration. In this particular case, the oxidizing flux is forced across the carbon black deposit, oxygen diffusion being insignificant. A good agreement between experimental results and model predictions is obtained, proving the rate constants validity.

• OSTI ID: 5575019
• Journal Information: Combustion and Flame; (United States), Vol. 95:1-2; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
02 PETROLEUM
CARBON BLACK
OXIDATION
DIESEL FUELS
COMBUSTION KINETICS
SOOT
ACTIVATION ENERGY
DIFFUSION
MATHEMATICAL MODELS
OXYGEN
POROSITY
POROUS MATERIALS
THERMAL GRAVIMETRIC ANALYSIS
CARBON
CHEMICAL ANALYSIS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DISTILLATES
ELEMENTS
ENERGY
ENERGY SOURCES
FOSSIL FUELS
FUELS
GAS OILS
GRAVIMETRIC ANALYSIS
KINETICS
LIQUID FUELS
MATERIALS
NONMETALS
PETROLEUM
PETROLEUM DISTILLATES
PETROLEUM FRACTIONS
PETROLEUM PRODUCTS
QUANTITATIVE CHEMICAL ANALYSIS
REACTION KINETICS
THERMAL ANALYSIS
400800* - Combustion
Pyrolysis
& High-Temperature Chemistry
025000 - Petroleum- Combustion