Hydrogen and carbon dioxide adsorption with Tetra-n-Butyl ammonium semi-clathrate hydrates for gas separations

Hiroyuki Komatsu, Masaki Ota, Yoshiyuki Sato, Masaru Watanabe, Richard L. Smith

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)

Abstract

Gas adsorption rates of H2, CO2, and H2-CO2 gas mixture (H2/CO2=3.4) with tetra-n-butyl ammonium salt (bromide, chloride, and fluoride) semi-clathrate hydrate particles were measured at 269 K to assess their properties for gas separation. Equilibrium gas occupancies in the S-cages of the particles were in order of (high to low) for hexagonal structure-I, tetragonal structure-I, and superlattice of cubic structure-I structures with the maximum fractional occupancy by CO2 being about 40%. The CO2 diffusion rate depended on the anion size of the salt, which is attributed to distortion of the S-cage that is close to the molecular size of CO2. Simulations of semi-clathrate hydrate particles with theory showed that H2/CO2 selectivities could be as high as 36 (3.0 mol% TBAF) and that selectivities for an ideal membrane (3.3 mol% TBAF) could be >100 (269 K, 0.3-4.5 MPa). Semi-clathrate hydrates have wide application as separation media for gas mixtures.

Original languageEnglish
Pages (from-to)992-1003
Number of pages12
JournalAIChE Journal
Volume61
Issue number3
DOIs
Publication statusPublished - 2015 Mar 1

Keywords

  • Anion
  • Formation kinetics
  • Gas adsorption
  • Separations
  • Structure

ASJC Scopus subject areas

  • Biotechnology
  • Environmental Engineering
  • Chemical Engineering(all)

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