Pyrolysis of Naphtha Feedstocks: Automatic Generation of Detailed Kinetics and Lumping Procedures

This paper analyses and revises the critical steps in the computer generation of complex reaction schemes for pyrolysis reactions of naphtha feeds. Moving from the pioneering experience of the well known SPYRO kinetic model, the critical steps in the simplification and lumping procedures are explained, critically discussed and partially removed. The availability of parallel processors and always more efficient computer facilities allows enlarging the description details of the overall reacting system. With reference to typical naphtha feedstocks, different description evels of feed characterization and different simplifications of the reaction network can be used. Namely, a large number of branched paraffin isomers are used to characterize the feed and the effect of possible refinery treatments of the naphtha feed are discussed. Moreover, the complex reaction scheme of hydrocarbon pyrolysis needs to be simplified both in terms of decomposition and recombination reactions, in order to avoid an excessive increase of the overall dimension of the mechanism, without significant improvements in the obtained results. As a result of this kinetic study, the SPYRO kinetic scheme is further extended to cover new possible feeds and more complex situations. Several examples illustrate the advantages and the limits of the proposed approach.