A robust dynamic column breakthrough technique for high-pressure measurements of adsorption equilibria and kinetics

Thomas Saleman, Gongkui Xiao, Gang Li, Eric F. May

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)

Abstract

Adsorption equilibria and kinetics of N2 and CH4 on four adsorbents, namely commercial activated carbon Norit RB3, zeolite 13X, zeolite 4A and molecular sieving carbon MSC-3K 172, were measured at temperatures of (273 and 303) K in the pressure range of (25–900) kPa using an improved dynamic breakthrough apparatus. Equilibrium adsorption measurements were performed with breakthrough experiments, and sorption kinetics were measured with a chromatographic pulse technique to eliminate undesirable systematics such as buoyancy and limitations imposed by heat transfer in conventional breakthrough techniques. The differential equations governing the spreading of a pulse passing through the column were solved in the Laplace domain to reduce numerical dispersion and artefacts associated with solving these equations for adsorption in the time domain on a finite grid. A method for identifying the reliable measurement range of sorption rates (mass transfer coefficients) from 10−4 to 1 s−1 was proposed and demonstrated with the four adsorbents. The sorption rates for Norit RB3 and zeolite 13X had values above the upper resolvable limit of 1 s−1. The measured sorption rates for MSC-3K 172 and zeolite 4A were compared with values obtained independently using a static volumetric method on the same adsorbents at the same temperatures but over a lower pressure range (0–110 kPa) (Xiao et al., Adsorption 23 (2017) 131–147). The sorption rates obtained for the two adsorbents via these two independent techniques were consistent within the measurement uncertainty of each method, which significantly increases the confidence with which these values can be used in simulations of industrial PSA processes.

Original languageEnglish
Pages (from-to)671-684
Number of pages14
JournalAdsorption
Volume23
Issue number5
DOIs
Publication statusPublished - Jul 2017

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