Hydrogen and carbon dioxide adsorption with tetra‐n‐butyl ammonium semi‐clathrate hydrates for gas separations. Issue 3 (3rd December 2014)

• Record Type: Journal Article
• Authors: Komatsu, Hiroyuki; Ota, Masaki; Sato, Yoshiyuki; Watanabe, Masaru; Smith, Richard L.
• Is Part Of: AIChE journal. Volume 61:Issue 3(2015:Mar.)
• Page Start: 992
• Page End: 1003
• Publication Date: 2014-12-03
• Subjects: Chemical engineering -- Periodicals; Génie chimique -- Périodiques; 660.28
• DOI: 10.1002/aic.14689
• Languages: English
• ISSNs: 0001-1541

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p>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 &gt;100 (269 K, 0.3–4.5 MPa). Semi‐clathrate hydrates have wide application as separation media for gas mixtures. © 2014 American Institute of Chemical Engineers <italic>AIChE J</italic>, 61: 992–1003, 2015</p> </abstract>