Thermal diffusion and flow property of CO2/CH4 in organic nanopores with fractal rough surface

Abstract

The kerogen is rich in complex pore networks with a random rough surface, which is a factor controlling the thermal diffusion and flow property of gases. In this work, we construct organic-rich nanopore with fractal surfaces by inserting and deleting carbon atoms. The adsorption ability, thermal diffusion property, and flow velocity of CO 2 /CH 4 in the nanopore are analyzed using with molecular simulations. The results showed that the adsorption capacity of CO 2 is nearly twice that of CH 4 , which is decided by adsorption enthalpy, whereas the maximum thermal diffusion ability of CO 2 is only 23.7% that of CH 4 . With external pressure gradients imposed on the system, the flow speed of CO 2 was lower than that of CH 4 for nanopores with different roughness. These findings provide a theoretical basis for the feasibility of CO 2 exploitation of shale gas.

Simulation of Methane Occurrence in Rough Nanokerogen Slits

“…Shang et al 28 constructed fractal nanopores based on fractal theory to simulate gas adsorption. He et al 29 constructed a rough slit based on the Weierstrass−Mandelbrot function, which was used to study the effect of slit roughness on gas flow. The advantage of random methods is that they are highly targeted, establish specific functions for the studied problem, and produce models corresponding to the research content.…”