Molecular Simulations of Supercritical Fluid Permeation through Disordered Microporous Carbons

Alexandru Botan (1, 2) , Romain Vermorel (1, 2, 3) , Franz-Josef Ulm (1, 2) , Roland J.-M. Pellenq (4, 1, 2)

1 MIT - Massachusetts Institute of Technology
2 MSE 2 - Multiscale Material Science for Energy and Environment
3 LFCR - Laboratoire des Fluides Complexes et leurs Réservoirs
4 CINaM - Centre Interdisciplinaire de Nanoscience de Marseille

Fluid transport through microporous carbon-based materials is inherent in numerous applications, ranging from gas separation by carbon molecular sieves to natural gas production from coal seams and gas shales. The present study investigates the steady-state permeation of supercritical methane in response to a constant cross-membrane pressure drop. We performed dual control volume grand canonical molecular dynamics (DCV-GCMD) simulations to mimic the conditions of actual permeation experiments. To overcome arbitrary assumptions regarding the investigated porous structures, the membranes were modeled after the CS1000a and CS1000 molecular models, which are representative of real microporous carbon materials. When adsorption-induced molecular trapping (AIMT) mechanisms are negligible, we show that the permeability of the microporous material, although not significantly sensitive to the pressure gradient, monotonically decreases with temperature and reservoir pressures, consistent with diffusion theory. However, when AIMT occurs, the permeability increases with temperature in agreement with experimental data found in the literature.

Domaines: Chimie-Physique [physics.chem-ph]; Agrégats Moléculaires et Atomiques [physics.atm-clus]; Science des matériaux [cond-mat.mtrl-sci]; Mécanique des fluides [physics.class-ph]; Mécanique des fluides [physics.class-ph]; Dynamique des Fluides [physics.flu-dyn]; Génie des procédés; Matériaux; Milieux fluides et réactifs

Alexandru Botan, Romain Vermorel, Franz-Josef Ulm, Roland J.-M. Pellenq. Molecular Simulations of Supercritical Fluid Permeation through Disordered Microporous Carbons. Langmuir, 2013, 29 (32), pp.9985-9990. ⟨10.1021/la402087r⟩. ⟨hal-00856240⟩