Following the conceptual demonstration
of high separation efficiency
and column capacity obtained in olefin/paraffin distillation using
hollow fiber structured packings (HFSPs) in a bench scale (J. Membr. Sci.
2006, 2007, and 2010), we scaled-up this process with a 10-fold increase in
the internal flow rate and a 3-fold increase in the module length.
We confirmed that the HFSPs technology gives high separation efficiency
and column capacity in iso-/n-butane
distillation for 18 months. We systematically investigated the effects
of packing density, concentration of light component, reflux ratio,
and module age on the separation efficiency and operating stability.
Comprehensive characterizations using scanning electron microscopy
(SEM), Brunauer–Emmett–Teller (BET), thermogravimetric
analysis (TGA), differential scanning calorimetry (DSC), and dynamic
mechanical analysis (DMA) were carried out to probe the changes in
the morphological, thermal, and mechanical properties of polypropylene
(PP) hollow fibers over the aging process. The results suggest that
after a long-term exposure to light hydrocarbon environments at ≤70
°C the morphological and mechanical properties of the PP polymer
do not degrade significantly in a propane/propylene and iso-/n-butane environment.