Colloids and Surfaces A: Physicochemical and Engineering Aspects ( IF 5.2 ) Pub Date : 2021-09-25 , DOI: 10.1016/j.colsurfa.2021.127630 Zhi-wei Zhang 1 , Guang-dong Zhang 1 , Chao-ping Mo 1
China's Puguang gas field has abundant reserves of high sulfur-bearing natural gas, but sulfur deposition problems have hindered the development of the reservoir. Many experimental and predictive models have been applied to this issue, but few studies have addressed it from a microscopic perspective. Thus, we developed a molecular model of calcite and monolithic sulfur, studied the adsorption mechanism of sulfur molecules on the calcite {104} surface using Monte Carlo and molecular dynamics methods, and analyzed the effects of temperature, pressure, and pore size on the adsorption process. The study showed that the heat of adsorption grew faster at low pressure and stopped growing after reaching the equilibrium pressure. Increasing the temperature or pore size decreased the saturation heat of the adsorption. The excess adsorption results proved that the adsorption was chemisorption, i.e., a slow and irreversible monolayer adsorption process. The calculated radial distribution function gave the adsorption layer a thickness of about 2.2 Å. The adsorption effect was optimal at a pore size of 2 nm, but the diffusion coefficient of the adsorption layer was more prominent for larger pore sizes. However, pore sizes above 4 nm disturbed the distribution pattern of the sulfur inside the pores.