The kinetics of complex reaction systems were studied on molecular scale with the combined method of Monte Carlo simulation and Structural Oriented Lumping by focusing on deep catalytic cracking (DCC)

the model parameters were optimized with the regular analytic data of a DCC-Ⅰ unit. A model was established to transform the feedstock of the complex reaction systems such as DCC-Ⅰ to 1000 molecules with Monte Carlo simulation and every molecule was expressed by 19 attributes. The results of model simulation showed that these 1000 molecules reflected the characters of feedstock very well and their average properties gave a good agreement with the plant data.