With increasing environmental concerns, gasoline and lubricant oils with high octane number are being preferred as they result in reduced emissions from vehicles. Octane number of high molecular weight hydrocarbons can be increased by selectively isomerizing and cracking them into low molecular weight hydrocarbons. Catalytic hydroisomerization and hydrocracking is an important process to selectively branch and crack high molecular weight hydrocarbons in the petroleum industry. Research in modelling of these reactions is primarily
based on characterizing and quantifying the vast network of reactions taking place in hydroisomerization and hydrocracking. This particular work focuses on reaction modelling of hydroisomerization and hydrocracking of n-Heptane in bifunctional catalysts based on Single Event Microkinetic (SEMK) approach. SEMK is a novel approach, which takes into account every fundamental step occurring in the vast reaction network and accounts for contribution of each of these steps to overall reaction rate. Results obtained via modelling by SEMK approach were fitted to experimental results in order to obtain estimates of rate constants of elementary steps.
An SEMK based model was created in three phases: reaction network generation, obtaining kinetic coefficients via SEMK model and development of rate equations and reactor model. The concentrations of individual species obtained from the model were fitted into experimental results to get estimations of kinetic rate coefficients of elementary steps. Estimations of these coefficients were obtained at three different temperatures (519K, 531K and 544K). A thorough analysis of results was performed in three parts. In the first part, the mass balance across the reactor is observed to ensure credibility of results obtained under steady state reactor conditions. In the second part, the product distribution of all components across the reactor was analyzed and compared with experimental results. It was observed that the product profiles fitted well with experimental observations for species formed in considerable amounts. In the third part, estimations of kinetic rate coefficents were obtained and compared with literature trends. It was observed that the parameters mostly followed literature trends. In the end recommendations are provided for overcoming the shortcomings of the present model for future study.