Tapered element oscillating microbalance (TEOM) studies of isobutane,n‐butane and propane sorption in β‐ and Y‐zeolites |
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| Authors: | Kening Gong Bala Subramaniam Palghat A Ramachandran Keith W Hutchenson |
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| Affiliation: | 1. Center for Environmentally Beneficial Catalysis and Dept. of Chemical and Petroleum Engineering, University of Kansas, Lawrence, KS 66045;2. Center for Environmentally Beneficial Catalysis and Dept. of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130;3. DuPont Co., Wilmington, DE 19880 |
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| Abstract: | A TEOM is used to elucidate the adsorption/desorption characteristics of alkylation reactants on USY‐ and β‐zeolites. Equilibrium adsorption isotherms were obtained on USY‐ and β‐zeolites using n‐butane, isobutane and propane as proxy reactant molecules (T = 303–398 K, adsorbate partial pressure 0–1.2 bar). Analysis of the transient adsorption/desorption profiles of these molecules from either a bed of the zeolite or pelletized particles of the crystals (with mean size < 1 μm) demonstrate that diffusion in the secondary meso‐/macroporous structure formed in the packing or the pellets controls the overall sorption rates. The experimental adsorption/desorption profiles from the pelletized zeolites were regressed with available mathematical models to obtain effective meso‐/macropore diffusivities for reactant molecules, and nearly perfect fits of the experimental and the modeled profiles. Taking into account the dead volume in the system, a criterion for reliable measurements of either micropore or mesopore diffusivities by the TEOM technique is derived. © 2009 American Institute of Chemical Engineers AIChE J, 2010 |
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| Keywords: | adsorption desorption diffusion zeolites TEOM |
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