Molecular dynamics simulation of sulphur nucleation in S–H₂S system

Abstract

The mechanism of sulphur nucleation in S–H₂S system is investigated by molecular dynamics simulation with the ReaxFF reactive force field. The results indicate that the nucleation of sulphur requires certain conditions. The nucleus of sulphur will form once the allotropes of sulphur dissolve from polysulphanes. Separate sulphur atoms aggregate into the cluster in the initial stage of nucleation according to the snowball effect. The cluster of nucleation is judged by the average distance of the neighbour sulphur atoms, which is identified as 2.8 Å through a parametric study. The sustainable process of nucleation depends on whether the cluster can overcome its critical state. The formation of the cluster may accelerate its own nucleation/coalescence and H₂S decomposition.

Keywords:

• sulphur
• nucleation
• hydrogen sulphide
• molecular dynamics simulation

Acknowledgements

This work is supported by Open Fund (PLN1016) of State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation (Southwest Petroleum University). X. Chen is supported by National Science Foundation (CMMI-0643726), DARPA (W91CRB-11-C-0112), National Natural Science Foundation of China (11172231), and World Class University programme through the National Research Foundation of Korea (R32-2008-000-20042-0).