Effect of Different sp² Bond Contents on the Reactivity and Mechanical Properties of Coke Carbon: A ReaxFF Molecular Dynamics Study

ZX Xiong and KJ Li and YS Bu and Z Liang and H Zhang and HT Liao and F Zhou and JL Zhang, ACS OMEGA, 8, 37043-37053 (2023).

DOI: 10.1021/acsomega.3c04411

In this study, ReaxFF-MD was used to construct a large-molecule model of coke containing 3000 atoms, and the sp(2) bond content of the model was controlled by changing the heating and cooling rates. The increase of the sp(2) bond content led to a significant difference in the reactivity of coke. The presence of the sp(2) bond caused the carbon atoms inside the coke to change into a circular structure, making it more difficult for the gaseous atoms to adsorb on the surface of the coke. It significantly reduced the gasification reaction rate of coke in the CO2 and H2O atmospheres. In the tensile simulation experiment, it was found that the stretching process of coke was mainly divided into three stages: an elastic stretching stage, a plastic stretching stage, and a model fracture stage. During the stretching process, the carbon ring structure would undergo a C-C bond fracture while generating carbon chains to resist stress. The results indicated that the presence of sp(2) bonds can effectively reduce the phenomenon of excessive local stress on coke to improve its tensile resistance. The method developed in this paper may provide further ideas and platforms for the research on coke performance.

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