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.