Investigation of kerogen thermal decomposition mechanisms and kinetics via ReaxFF molecular dynamics simulations

This study investigates the mechanisms and kinetics of kerogen thermal decomposition using molecular dynamics simulations with the ReaxFF force field. The cook-off simulation at the constant heating rate shows that the decomposition of kerogen begins with the cracking at terminals and weaker linkages of kerogen molecule, and the final products are formed by radicals recombination, dehydrogenation, and other reactions. The Flynn-Wall-Ozawa kinetic analysis based on the thermal decomposition simulations at various heating rates shows that the activation energy increases with the conversion of decomposition. These results reveal the thermal decomposition mechanisms and the thermal stability of kerogen in different stages during the process of thermal decomposition.