Construction of Ring-Bridge Archipelago Model of Oil Sands Bitumen Based on Molecular Simulation and Study on Its Pyrolysis Characteristic

Abstract

To efficiently utilize oil sands resources, enhance their strategic position among traditional energy sources, and deeply reveal the essence of the pyrolysis reaction of oil sands bitumen (OSB), this study integrates experimental characterization with molecular simulation techniques. This paper innovatively adopts the “ring-bridge archipelago” method to construct two-dimensional molecular structure models of OSB from Karamay, Xinjiang (KXC), China, and Buton Island (DBI), Indonesia, with chemical formulas of C250H349N3O5 and C250H369NO10S9 respectively. The results showed that although DBI and KXC differ in elemental composition, their molecular structural characteristics are highly similar. Notably, the carbon–sulfur bonds in sulfoxide groups, the carbon–carbon bonds in alicyclic rings, and the carbon–oxygen bonds in aliphatic ethers exhibit high pyrolytic activity. Based on multidimensional analysis results, a novel simplified pyrolysis reaction mechanism model for OSB chemical structures is proposed. This model clarifies the selective bond cleavage characteristics in the pyrolysis system and identifies differences in bond order and recombination reactions during pyrolysis as key factors driving selective bond cleavage.