Analysis of thermodynamic equilibrium yield and process simulation for catalytic pyrolysis of light hydrocarbons based on one set of independent reactions

The catalytic pyrolysis of light hydrocarbons has been regarded as a promising route for satisfying the growing demand for light olefins. This study established a thermodynamic equilibrium model based on one set of independent reactions in the catalytic pyrolysis process, for predicting the thermodynamic equilibrium yield and analyzing the effects of the operating conditions on the equilibrium yields. The trend of the equilibrium yields was consistent with the trend of the experimental yields. Thus, under the present operating conditions, determined by applying the thermodynamic equilibrium model, the production of light olefins was increased and the propylene/ethylene (P/E) ratio could be tailored to meet market demands. Then, an actual reaction degree model based on independent reactions was established and incorporated in Aspen Plus to simulate the catalytic pyrolysis process, and the reliability was validated experimentally. The thermodynamic equilibrium model and process simulation are easy to implement and can help to optimize the operating conditions and to predict the product yields for the catalytic pyrolysis of light hydrocarbons.