Mitigation of sulfide adsorption in natural gas by silanized stainless steel: insights from density functional theory

Abstract

Abstract This study employs Density Functional Theory (DFT) to investigate the inhibition of sulfide adsorption in natural gas through the use of silanized stainless steel. Various adsorption models were developed to explore the interactions between hydrogen sulfide, thionyl carbon, methyl mercaptan, and ethyl mercaptan with silanized stainless steel surfaces. Calculations revealed positive adsorption energies of 1.55 eV, 1.87 eV, 1.56 eV, and 1.60 eV, respectively, indicating a non-spontaneous adsorption process. Furthermore, the adsorption configurations of these sulfur compounds on the surface closely resembled their free states, indicating weak interactions with the surface. Charge population analysis indicated minimal charge transfer between the sulfides and the silanized stainless steel, suggesting dissociative chemical adsorption is unlikely. Experimental results, corroborated by theoretical predictions, demonstrate that the silanization coating serves as an inert shield for stainless steel, effectively resisting sulfide adsorption. A 60-day adsorption test confirmed stable concentrations of sulfide gases with minor fluctuations, validating the efficacy of silanization treatment in hindering sulfide adsorption.