The pressure-temperature explosion limits of H 2 /CH 4 /O 2 mixtures were analyzed computationally and analytically. It is shown that, with the addition of around 5% of H 2 to the mixture, the explosion limit evolves from being monotonic to the non-monotonic Z-shaped response characteristic of H 2 /O 2 explosions. Such transition is much less sensitive compared to the H 2 /CO/O 2 system, and is explained by the different responses of the kinetic parameters corresponding to O and OH radical competitions by H 2 and CH 4. It is further shown that the explosion limits at various conditions can be reproduced well with a reduced mechanism of 22 elementary steps and 17 species. Further eigenvalue analysis with quasi-steady state simplification leads to accurate analytic solutions for the explosion limits, with explicit expressions for the controlling pathways for different H 2 and CH 4 concentrations. Both linear radical-reactant reactions and nonlinear radical-radical reactions of H 2 and CH 4 oxidations are investigated, leading to enhanced insight of this foundational component in the mechanisms of hydrocarbon oxidations and of the efficient utilization of natural gas.
All Science Journal Classification (ASJC) codes
- General Chemical Engineering
- Mechanical Engineering
- Physical and Theoretical Chemistry
- Eigenvalue analysis
- Explosion limits