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Indexed by:期刊论文

Date of Publication:2017-03-15

Journal:MICROPOROUS AND MESOPOROUS MATERIALS

Included Journals:SCIE、EI

Volume:241

Page Number:185-191

ISSN No.:1387-1811

Key Words:Spontaneous liquid-gas imbibition; Carbon molecular sieves; Kinetics; Air separation; Micropores

Abstract:The kinetics of spontaneous liquid-gas imbibition in micropores of carbon molecular sieves (CMSs) used for air separation has been investigated. Based on the kinetics, the microporous textures of CMSs could be estimated, and a new assessment method for O-2/N-2 separation performance of CMSs in pressure swing adsorption (PSA) was established. Water was chosen as the imbibition liquid probe, and N-2 and O-2 were chosen as the gas probes. The pseudo-second-order (PSO) kinetic model and the linear driving force (LDF) model were employed to confirm that the rate-limiting steps of the spontaneous water-O-2/N-2 imbibition were mainly attributable to the surface adsorption of water and the diffusion of gas through the micropore entrence or interior in CMSs. Water molecules invade into the narrower micropore mouths prior to the wider micropore mouths. An O-2/N-2 selectivity coefficient K was established to assess the air separation performance of CMSs. When the K value is equal to zero, the size distribution of micropore mouths in CMSs is the fittest for the air separation and the highest N-2 production can be obtained. But with K gradually deviating zero, the air separation performance of CMSs decreases. (C) 2017 Elsevier Inc. All rights reserved.