Molecular Dynamics Simulation of Natural Gas Sweetening Using the Ionic liquids Based on 1-Hexyl-3-Methyl Imidazolium

The solubility of natural gas components in ionic liquids at typical treatment conditionsencountered in gas streams, can be used to discover their high potential for acid gas removalscompared with traditional solvents [1].In this paper, the removing of hydrogen sulfide by 1-hexyl-3-methyl imidazolium chloride,hexafluorophosphate and tetrafluoroborate is investigated by the help of molecular dynamicssimulation. The simulations were carried on by NAMD [2] software and visualizations were doneby VMD [3].The natural sour gas was prepared by mixing 93.9% methane, 4.2% ethane, 0.3% propaneand 1.6% H2S. Here, the effect of anion type on the sweetening process is analyzed in terms ofstructural parameters and energetics of the distribution process. The structural parameters such asradial and spatial distribution functions and hydrogen bonds were measured, analyzed andinterpreted. As well as the interaction energies and the electrostatic and van der Waalsinteractions contributions in the total interaction energies between considered species weremeasured. Results show that all of the studied anions can absorb H2S from the prepared mixture,whiles the chloride contained ionic liquid has the maximum performance from structural andenergetics view of points.

Keywords:

Molecular Dynamics Simulation , Ionic liquid , Hydrogen Sulfide , Gas Sweetening