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Abstract
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The elimination of carbon dioxide (CO2) using water-based nanofluids (NFs) in a hollow fiber membrane contactor (HFMC) using polypropylene (PP) membrane was experimented. Gas flows in the shell, while NF flows in the fibers. Metal oxide nanoparticles (NPs) such as aluminum oxide (Al2O3), titanium dioxide (TiO2) and silica (SiO2) in the concentrations of 0.05, 0.1 and 0.2 wt% were used in the experiments. Some factors such as gas flow rates, NPs type, NF temperature, NP concentration, as well as the effect of particle size on the separation were investigated. The results clearly show that the highest flux of CO2 occurred for 0.2 wt% concentration of Al2O3 NFs. Mass transfer flux enhancement (MTFE) was defined as the relative mass transfer flux (MTF) of CO2 in the NFs with respect to the MTF of CO2 in the de-ionized water as the base fluid. MTFE changed from 1.29 to 2.25 for the Al2O3 NFs. Among all the results, the best result was obtained for Al2O3 (40 nm) at 1.6 Lit/min liquid flow rate, 25 ?C liquid temperature, 5 Lit/min gas flow rate and 40% inlet CO2 concentration which is 98.9% CO2 removal. Finally, a new correlation was developed for the Sherwood (Sh) number for the CO2 mass transfer in the NFs flowing in the fibers. Sh number was developed based on the NFs Reynolds (Re) number, NPs Reynolds (Renp) number, Schmidt (Sc) number, and NPs volume fraction with an average relative error percent (REP) of 1.6% and R2 of 0.99.
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