Molecular Level Simulation of the Conversion and Distribution of Sulfides in the Fluid Catalytic Cracking and Hydrotreating Processes to Improve the Cleanliness of Gasoline and Diesel

To meet the requirements of fuel standards, the coupling simulations of fluid catalytic cracking (FCC) and hydrotreating processes were carried out to analyze the conversion and distribution of sulfides at the molecular level to improve the cleanliness of gasoline and diesel. According to the structure-oriented lumping (SOL) method and the reaction mechanism, the transformation laws and distributions of sulfides in gasoline and diesel were studied. When the FCC reaction temperature increased, the content of dimethyl-thiophene in heavy gasoline and the content of dimethyl-dibenzothiophene in diesel increased due to the stronger promotion of high temperature to the side chain cracking reactions. As gasoline hydrotreating reaction temperature rose from 220 to 280 °C, the content of dimethyl-thiophene in heavy gasoline reduced from 4.77 to 0.98 mg/kg since higher temperature promotes the hydrodesulfurization reactions. The coupling simulation could provide effective guidance at the molecular level for reducing the content of sulfides in heavy gasoline and diesel.