The evolution of atomistic structure and mechanical property of coke in the gasification process with CO2 and H2O at different temperatures: A ReaxFF molecular dynamics study

Abstract

Molecular dynamics simulations with reactive force-eld (ReaxFF-MD) were performed to construct the molecular model of coke. The coke was placed in a mixed atmosphere of H 2 O/CO 2 with different concentration ratios to investigate the dissolution loss reaction. It was found that different atmospheric concentrations had different effects on the coke model structure and reaction sites. The CO 2 molecular tended to dissolve on the surface of coke and destroyed its surface structure, while the H 2 O molecular was more likely to enter the coke to destroy its structure, which was consistent with the experimental results. At the same time, the tensile simulation of the coke model after the reaction was carried out to observe the changes in the mechanical properties of the structure after the reaction. It was found that CO 2 and H 2 O have varying degrees of in uence on the mechanical properties of the coke model.Controlling the composition content of the reaction gas can effectively adjust the tensile resistance of the coke model. It was also found that different temperatures have an impact on the mechanical properties of the coke model, and the tensile resistance of the coke was poor at high temperatures. By revealing the behavior of coke model at the micro scale, it provides a theoretical basis for the industrial coke application process.