TY  - GEN
AV  - public
Y1  - 2007///
TI  - Evaluation of a Detailed Reaction Mechanism for Partial and Total Oxidation of C1 - C4 Alkanes
KW  - Kinetic Mechanism 
KW  -  Combustion 
KW  -  Partial Oxidation 
KW  -  CFD 
KW  -  Autoignition
ID  - heidok8338
A1  - Quiceno González, Raúl
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/8338/
N2  - In the present work a chemical kinetic mechanism was developed, suitable for modeling combustion and partial oxidation processes of C1 ? C4 alkanes. The gas-phase kinetic mechanism describes intermediate and high temperature chemistry. Accordingly, the formation and evolution of important intermediate gas-phase species: Olefins and oxygenates were described in terms of different pathways typical at those temperature regimes. A previously developed mechanism suitable for high temperature conditions was extended by including reactions which described the chemistry of total and partial oxidation of methane, ethane, propane, butane, lower alkenes and formation and consumption of their characteristic organic hydro-peroxide radicals and cyclical compounds. The kinetic mechanism was validated by comparing calculated results of ignition delay times, against experimental data obtained in shock tubes, for various hydrocarbons and their mixtures, over a wide range of reaction conditions (temperature, pressure and mixture composition). Further, the kinetic mechanism was evaluated by comparing numerical simulations against experimentally obtained concentration profiles of the main gas-phase species, measured in jet stirred reactors for different  hydrocarbons and their mixtures during partial oxidation. Next, the mechanism was applied to get a better understanding of the interactions between flow, mass transfer and homogeneous-heterogeneous chemistries during the catalytic partial oxidation of methane in a short contact time reactor, which has recently attracted strong scientific and technological interest. The detailed study of the catalytic partial oxidation of methane to syngas in a single gauze reactor was based on three-dimensional numerical simulations of the flow field coupled with heat transport and multi-step gas-phase and surface reaction mechanisms, including the computation of the surface coverage. Results from the model were compared with experimental data reported in the literature. The gas-phase mechanism was modeled using a reduced mechanism, and for the surface a previously developed mechanism was adapted. The results from the simulation of the partial oxidation of methane in a short contact time reactor were carried out using the commercial computational fluid dynamics code Fluent, which was coupled with external subroutines to model the detailed gas-phase and surface chemistry. Today, the production of synthesis gas (carbon monoxide + hydrogen) is currently carried out via steam reforming. In that process steam passes over a carbon source, often methane or coal, and is heated to produce the synthesis gas. Synthesis gas is extremely valuable commercially for the production of methanol, hydrocarbons, higher alcohols for use in detergents, and ammonia to use in fertilizers. There is also a significant interest in the production of hydrogen for fuel cells. However, steam reforming has the major disadvantage of being endothermic and hence requires a large amount of wasted energy to drive the reaction. An alternative to steam reforming is the partial oxidation of the hydrocarbons, especially methane in short contact time reactors. This promising route for natural gas conversion into more useful chemicals has the advantage of being auto thermal.
ER  -