Coupling Simulation and Intelligent Optimization of Fluid Catalytic Cracking and Hydrotreating Processes Based on the Molecular Level

The petrochemical industry is highly dependent on foreign countries for process simulation soft-ware; moreover, the National VI fuel standards put forward more stringent requirements for the content of specific molecules or components in automotive gasoline and diesel. It is urgent to understand the composition of petroleum at the molecular level and accurately control the quality indexes of gasoline and diesel through molecular coupling simulation and intelligent optimization. Guided by the molecular oil refining, based on the structure-oriented lumping (SOL) method, the study constructs the coupling model of fluid catalytic cracking (FCC) and hydrotreating processes at the molecular level. Then the coupling model has been used to discover the synergistic transformation laws of oil molecules and investigate the effects of reaction temperatures on the distribution of hydrocarbon and non-hydrocarbon molecules. The results show that when the FCC reaction temperature is increased from 500 to 560 °C, the mass fraction ratio of methyl pentane to methyl pentene can decrease from 2. 90 to 1. 63; on a molecular level, this demonstrates that the low reaction temperature is conducive to the hydrogen transfer reactions and the decrease of olefin content in gasoline. When the reaction temperature of gasoline hydrotreating is increased from 220 to 280 °C, the mass fraction of dimethyl thiophene in gasoline can be reduced from 3. 87 to 1.35 mg/kg; on a molecular level, this demonstrates that the high reaction temperature is conducive to the hydrodesulfurization reactions and the decrease of sulfur content in gasoline. Molecular coupling simulation and intelligent optimization can provide a guidance for precise control of quality indexes of gasoline and diesel, aiming to establish a basic model based on reaction mechanisms for the construction of smart refineries. © 2024 Editorial Office of Acta Petrolei Sinica. All rights reserved.