Adsorption Equilibria and Kinetics of Propane and Propylene on Zeolite 13X Pellets

Jae-Jeong Kim, Seung-Jun Lim, Hyungwoong Ahn, Chang-Ha Lee

Research output: Contribution to journalArticlepeer-review

Abstract

The adsorption equilibria and kinetics of propane and propylene
on zeolite 13X pellets were investigated using a volumetric sorption
method at 283-363 K at pressures up to 650 kPa for propane and 750 kPa
for propylene. The difference between the adsorption saturation
capacities of the two gases on zeolite 13X was not high, with a value of
2.95 mol/kg for propane and 3.34 mol/kg for propylene at 303 K. However,
the difference in the adsorption affinity for propane and propylene was
more noticeable in the lower pressure region. Experimental isotherms were
fitted using the dual-site Langmuir model with temperature-dependent
parameters. The isotherms of propane could be predicted well at low and
high pressures using the model, while in the propylene isotherms, the
deviation of the model was significant in the low-pressure region.
Therefore, it was highly recommended to use the isotherm model, obtained from the isotherm data in the range of propylene partial pressure in mixtures, for the design of adsorptive separation processes. The experimental uptake curves were fitted with either a piezometric model for the first concentration step (very low pressures) or a non-isothermal sorption model in the range of 10-40 kPa to extract the apparent reciprocal diffusion time constants. In the low-pressure region, the apparent diffusivities of propane were slightly greater than those of propylene, which is likely due to the difference in the kinetic diameters of the two gases. Subsequently, the dominant diffusion step of gas diffusion into the bi-dispersed zeolite 13X pellet was analyzed.
Original languageEnglish
Pages (from-to)286-298
Number of pages13
JournalMicroporous and Mesoporous Materials
Volume274
Early online date27 Jul 2018
DOIs
Publication statusE-pub ahead of print - 27 Jul 2018

Keywords

  • Zeolite 13X pellet
  • Propane
  • Propylene
  • Equilibrium
  • KINETICS

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