Simulation of Reaction Pathways of Sulfur Compounds and Product Properties Based on the Molecular-Level Hydrotreating Reaction Model

A molecular-level reaction model for the diesel hydrotreating process was established by using the structure-oriented lumping (SOL) method. A molecular composition matrix was applied to represent the hydrotreating feed molecular composition and was calculated as the model input. By following the 38 hydrotreating reaction rules, each molecule of the feed molecular composition matrix was able to react and automatically generate reaction pathways and eventually form a large reaction network containing 37,097 reactions. The SOL model had the advantage of carrying out the molecular kinetic difference, especially for sulfur-containing molecules. The hydrodesulfurization reaction (HDS) of dibenzothiophene preferred the direct desulfurization pathway rather than the hydrogenation pathway (HYD), while 4,6-dimethyl dibenzothiophene was more dependent on HYD for HDS. The hydrotreating model could calculate the product distribution and molecular composition accurately. Combined with the structural increment contribution method, the model extended the function of predicting the product properties. The hydrotreating reaction model realized the molecular-level description of the whole process including the feed molecular composition, the reaction process, and the product molecular composition and properties.