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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.

Mixtures of CO2 and argon, or helium, were used to continuously produce CO2 hydrate slurries at high linear fluid velocities and high gas volume fractions. The impact of gas carrier, fluid velocity, and slurry loading on heat transfer processes were investigated using a tubular continuous flow reactor. Due to the high gas volume fraction, the thermal conductivity of the carrier gas was found to significantly impact the heat transfer rate on the process fluid side. The overall heat transfer coefficient from a He/CO2 gas mixture was found to be at least 50% higher than that obtained from a comparable Ar/CO2 mixture. High fluid velocity in the hydrate formation reactor resulted in effective interphase mixing and, thus, enhanced both mass and heat transfer between the gas, liquid, and solid phases. With vigorous mixing, hydrate formation kinetics were very favorable and hydrate formation became heat-transfer limited.