Computer Generated Pyrolysis Modeling: On-the-Fly Generation of Species, Reactions, and Rates

The development of an integrated system for the computer generation of kinetic models is described. Required input is the structure of the reactants, the reaction rules, and the parameters of a structure/property kinetics correlation. The algorithm transforms this information into reactant/product relationships, i.e., the reaction network, species properties, rate constants, and the FORTRAN code corresponding to the governing species' balance equations, and offers a solution capability. Graph theory is exploited to represent the constituent atoms of a molecule to allow determination of species' uniqueness, implement chemical reactions, and identify reaction products. Special attention was devoted to improved algorithm efficiencies, the handling of ring systems, and on-the-fly'' quantum chemical calculations. This general approach is described in using ethane and cyclohexane pyrolysis case studies. The increase in the number of equations and number of components for ethane pyrolysis was exponential with the carbon number of allowed species.