Molecular modeling of carbon dioxide transport and storage in porous carbon-based materials

摘要

To fundamentally study the molecular processes in porous carbon-based systems relevant to transport and storage of carbon dioxide, non-equilibrium molecular dynamics simulations have been carried out with an external driving force imposed on a carbon-based 3-D pore network. The purpose of this study is to investigate the transport properties of pure carbon dioxide, methane and nitrogen as well as binary mixtures nitrogen and carbon dioxide and also methane and carbon dioxide through modeled 3-D carbon-based systems representative of porous carbon-based materials. The 3-D pore network has been generated atomistically using the Voronoi tessellation method of a structure containing approximately 125,000 atoms. Simulations have been carried out to determine the effect of the pore structure, exposure to an external potential and composition mixture on phenomena such as fluid distribution in the system and permeability for broad ranges of conditions. The results indicate that the morphological characteristics and energetic effects play a dominant role in the flow and transport properties of fluids. As expected among these factors, the porosity of the structure strongly affect the permeability. In addition, our simulation results indicate that the permeability is zero below a critical porosity of about 0.2 due to the low connectivity in the pore network.