This study successfully applied reactive force field (ReaxFF) molecular dynamic simulations to study the two-stage transformation of kerogen: initially transforming into pyrolytic bitumen and then into final products. It was found that the carbon–oxygen bond in the kerogen skeleton chain breaks first, while further transformation involves significant carbon–carbon bond breakage. Specifically, carbon–carbon bond breakage contributes almost 66.7% to pyrolytic bitumen formation, and nearly 80% to the final product formation. In addition, higher heating rates favor higher bond rupture speed and lead to a decline in heteroatoms within shale oil. In summary, this work provides more atomic insights of oil shale kerogen decomposition.
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