Summary: Application of Computational Kinetic Mechanism Generation to
Model the Autocatalytic Pyrolysis of Methane
Jeffrey M. Grenda,* Ioannis P. Androulakis, and Anthony M. Dean
Corporate Strategic Research, ExxonMobil Research & Engineering Company, Annandale, New Jersey 08801
William H. Green, Jr.
Department of Chemical Engineering, Massachusetts Institute of Technology,
Cambridge, Massachusetts 02139
An automated computational mechanism-generation technique is applied to construct elementary-
step chemical kinetic reaction models for the pyrolysis of methane at 1038 K and 0.58 atm.
Under these conditions, the pyrolysis process is extremely complex and exhibits autocatalysis.
The mechanism-generation approach constructs a detailed set of elementary reactions, retrieves
or estimates required reaction rates and thermochemistry, and constructs a kinetic model that
gives excellent agreement with experimental data for several species. Key to the success is a
newly developed capability of the algorithm to identify pressure-dependent chemically activated
reactions. A rate-based species-selection methodology is used to determine kinetically significant
species, and the algorithm is demonstrated to identify critical low-concentration byproducts.
Multistep chemically activated reactions involving the formation of cyclopentadiene and
subsequent hydrogen atom production are found to be important reactions, agreeing with previous
literature findings. The present work demonstrates that computer-generated kinetic models can
quantitatively predict experimental behavior for conditions where reaction rate constants and