Effect of fiber packing density on physical CO2 absorption performance in gas–liquid membrane contactor

• The effect of different fiber packing density was studied in membrane contactor.
• Increasing packing density produces decreasing trend of CO2 absorption flux.
• Overall mass transfer resistance reduced with increasing packing density.

Microporous polyvinylidene fluoride (PVDF) hollow fiber membranes were fabricated via wet-spinning process. The prepared fibers were characterized in terms of gas permeation, wetting pressure and membrane morphology. Physical absorption of CO2 from distilled water was conducted through the gas–liquid membrane contactors. The overall mass transfer resistance of the membrane system was evaluated using Wilson plot analysis. The spun membranes have good gas permeability, high wetting pressure and reasonably effective surface porosity which is appropriate for mass transfer between gas and liquid phases. It was found that by increasing the packing density of the membrane module, CO2 absorption flux decreases with reductions in liquid velocity. At increasing packing densities of up to 13%, liquid side resistance contributed to more than 90% of the overall mass transfer resistance due to ‘dead zone’ phenomena. The overall mass transfer coefficient of the module increased as the packing density increased from 2.6% to 13%. A clear trend of mass transfer resistance can be observed when the fiber packing density was varied accordingly in gas–liquid membrane contactor systems.