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Model based catalyst design is an emerging methodology in the development of new catalytic materials with properties tailored to the needs of specific industrial applications. A Single-Event MicroKinetic model (SEMK) was used to assess the hydrocracking behavior of n-dodecane, 4,4,6-trimethyl nonane and 2,5,8-trimethyl nonane, on a non-selective USY zeolite. The differences in cracking pattern exhibited by the various feed molecules provide guidelines for the control of the cracked product distribution through modifications of the zeolite pore structure. The connection of ZSM-22 type channels to the zeolite Y super cage is considered in this work. The percentage of C 6 products obtained by central cracking in the chain can be increased from 25% up to 93% by the design of an appropriate zeolite topology combining USY-like super cages with ZSM-22 like channel segments. This is a promising approach for the development of zeolite catalysts for the selective hydrocracking of Fischer Tropsch waxes into middle distillates.

The assessment of intrinsic reaction kinetics in the presence of diffusion limitations within a porous material remains one of the key challenges within the field of catalysis. The model-guided design of medium-pore zeolite catalysts which typically give rise to mass transport limitations would offer a feasible alternative to conventional trial-and-error procedures. Intracrystalline diffusion limitations during n-hexane hydroconversion on Pt/H-ZSM5 were assessed using an integrated Stefan–Maxwell, mean field, and Single-Event MicroKinetic (SEMK) methodology. The former theory quantifies multicomponent diffusion through a microporous substituent from pure component properties, while framework parameters inherent to the ZSM5 topology are incorporated via a mean field approximation. The complex chemistry involved in n-hexane hydroconversion was described by an SEMK model which is based upon the reaction family concept. Model regression against experimental data resulted in excellent agreement between the model and experiment. In addition, the estimated values for, among others, the component diffusion coefficients were physically meaningful. A sensitivity analysis of the catalyst descriptors demonstrated that especially the total acid site concentration and the crystallite geometry impact the catalyst activity and product distribution, establishing them as critical catalyst design parameters.

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A fluid catalytic cracking (FCC) unit has been simulated by integrating FCC riser reactor and regenerator models. This simulation uses a new10-lump riser reactor kinetic model developed in-house. The lumping scheme and reactions are based on more detailed description of the feed in terms of PNA (paraffins, naphthenes, and aromatics) in both light and heavy fractions. An artificial neural network (ANN) model, also developed in-house, relates routinely measured properties such as specific gravity, ASTM temperatures, and so on to the detailed feed composition needed for the kinetic model development. The conversion and product yields obtained by integrating the model equations were found to be in close agreement with those measured in the plant in all the cases investigated. Simulation results using the present model, when compared with results from a conventional 5-lump model, clearly brought out the improvement in prediction because of detailed feed description calculated from ANN models. A parametric sensitivity study was undertaken with respect to operating conditions such as effects of feed preheat temperature, feed flow rate, and reactor outlet temperature (independent variables) on the performance of the FCC unit, and the results have been discussed.