Abstract:
This research aimed to study the performance of microporous hollow fiber membranes in a gas-liquid absorption system. Tap water was used in the oxygen (O2) absorption study while deionized water was applied in carbon dioxide (CO2) absorption system. The experiments were conducted to determine the most effective operating conditions such as average membrane pore size, gas flow rate, liquid flow rate, the number of hollow fiber membranes, and concentration of gas phase. In addition, three types of surfactants (cationic, anionic, and nonionic) and different levels of turbidity represented by kaolin were applied to the absorption system as contaminants to investigate the effect of each parameter. Later, the mathematical models were established to estimate the expected outcome (kLa) which showed the absorption efficiency in both O2 and CO2 systems. As a result, membranes with microfiltration-size (0.1-3 microns) could provide higher absorption efficiency than membranes with ultrafiltration-size (0.01-0.1 microns). The overall mass transfer coefficient (kLa) for O2 absorption rose when increasing the liquid flow rate and the number of hollow fiber membranes. On the other hand, kLa decreased when surfactant and turbidity were present in the system. In addition, CO2 absorption system reported that increasing of liquid flow rate and carbon dioxide concentration could provide higher kLa especially up to 120 percent when sodium carbonate solution was added to liquid phase. Finally, the comparison of mass transfer between membrane contractor and bubble column indicated that membrane contactor has more efficiency than bubble column because of high surface area for mass transfer at the same size of bubble column. Thus, using the hollow fiber membrane contactor seems to be a better choice compared to using the conventional gas absorption system and bubble column.