Multiscale modeling of transport and residence times in nanostructured membranes

Abstract

Simulations based on its principles were performed using an ensemble of particles in a boundary-driven simulation cell, providing the average number of hits between a particle and the pore wall and the dependency of the residence time on the pore dimensions. The differences between operating a nanostructured membrane reactor in sweep-gas and pass-through modes were also investigated.

Blocking defects in SAPO-34 membranes with cyclodextrin

“…This is consistent with the permporometry estimate that a large fraction of defect flow before CD deposition is through pores larger than 30 nm. The permeance through smaller pores, where Knudsen and surface diffusion dominate, does not change with pressure [21]. After CD deposition, the CF 4 permeance decreased over the entire pressure range.…”

Development of a multiscale model for an atomic layer deposition process

“…Given the relatively low pressure of the ALD process and the small (e.g., 10's-100's nm) nanopore diameters, we find Knudsen numbers on the order of 1000, clearly indicating Knudsen diffusion as the primary precursor transport mode within the pore [2,12]. Based on the pore geometry illustrated in Fig.…”

“…''First-principles'' modeling [6] mostly has been limited to the initial growth of ALD films because of the computational difficulties associated with applying large-scale molecular dynamics to simulate growth of ALD films over multiple cycles. Likewise, gas-phase species transport within nanopores has been modeled by molecular dynamics and other sophisticated techniques [2]. However, the growth and transport models have yet to be coupled in a complete multiscale simulation of this deposition process.…”

Experiences with the publicly available multipurpose simulation code, Music

“…Albo et al [80] used a modified version of the Music code to study surface diffusion in nanopores. An analytical potential map representing the LJ contributions of the pore (host) atoms was created and used in their work.…”

“…The MD capabilities of the Music code have been used by various authors to study diffusion, [77][78][79][80] adsorption, [23,81] statistical mechanics of liquids [82] and tribology. [83] Compared with the usage of the GCMC module, the usage of the MD module has been smaller, presumably because of the abundance of other MD packages available.…”