Modeling catalytic methane partial oxidation with detailed chemistry

Detailed mechanisms are being promising, but they are not extensively used yet. Particularly in multi-phase reactions, their interaction with the transport phenomena is often underrated. Partial oxidation of methane in monolithic reactors (structured or foam-like) showed competitive in converting natural gas into syngas, an intermediate for the syntheses of higher hydrocarbons and methanol, or a new form of energy vector. Because of that, very many experimental data have been produced. In the present work this process is modeled, coupling transport phenomena and detailed kinetics. Several 1D models, of increasing accuracy, are applied to the square channel monolith: from the ideal PFR to a lumped model including solid conduction and both heat and mass transfer coefficients. Results show how the apparent stoichiometry changes if diffusional resistances are taken in account, slowing down the kinetics. The same geometry is solved also with the CFD, and results are compared to pseudo-homogeneous models. Also, the obtaining of the transfer coefficient by means of CFD is discussed. The foam monolith is modeled both with the PFR model and with a lumped model accounting for transport resistances, gas phase axial diffusion and solid conduction and radiation. Results are validated through spatially resolved measurements of temperature and composition. Differences between the bulk and the boundary layer compositions are ascribed to mass transfer resistances, as well as to the surface production rates. Sherwood numbers obtained from heat transfer correlations don't often agree with those calculated with the CFD, particularly if the reaction is fast: we suggest that Sh correlations should also account for the reaction order.