467335 Two Dimensional Nanosheets-Embedded Thin Film Composite Membrane for CO2 Cature Applications

Monday, November 14, 2016: 2:15 PM
Van Ness (Hilton San Francisco Union Square)
Ho Bum Park, Department of Energy Engineering, Hanyang University, Seoul, South Korea

The development of cost-effective CO2 capture technologies for coal power plants will reduce the adverse impact of CO2 emissions on global climate. Amine absorption technologies have been extensively studied and are regarded viable for post-combustion CO2 capture. However, the energy comsuption for absorption technologies is still much higher than minimum requirement for large scale post-combustion flue gas. It seems clear that the membrane-based gas separations have presented a suitable alternative to the traditional separation processes for CO2 capture, particularly for the treatment of flue gas streams including more than 15% CO2. Membrane systems offer relevant gains in terms of flexibility, reliability, modularity and that they need energy intensity generally lower, or, at least, comparable with that of absorption technology. For competition with existing technologies, most of all, membrane materials with high permeability and high selectivity should be further developed with feasible processibility for real membrane platforms such as hollow fibers or thin-film composite membranes. According to recent report, the membrane systems can compete with existing technologies when membrane shows high CO2 permeance (~4000 GPU, 1 GPU = 1×10-10 cm3(STP)/cm2.sec.cmHg) and high CO2/N2 selectivity (~50). However, to achieve this goal, many factors should be considered: selective layer thickness, gutter layer, and the porosity of support membrane in the form of thin-film composite membrane. In this study, we have developed high permeable, selective thin-film composite membrane for post-combustion CO2 capture. Selective layers consist of high CO2 permeable polymer and two-dimensional nanosheets. The nanosheets as dispersed phase in continuous polymer matrix help enhance CO2/N2 selectivity (~60) without any loss of CO2 permeability. Also, such nanosheets at low content help prevent CO2-induced plasticization, often leading to dramatic decrease in gas mixture. To develop high permeable, selective thin-film composite membranes, we have analyzed the effect of selective layer thickness, types of gutter layer (or gutter layer thickness), and support membrane properties, and these results were used for preparing optimized thin-film composite membranes. These thin-film composite membranes exhibited high CO2 permeance and high CO2/N2 selectivity, even in the presence of water, which is close to the membrane criteria suitable for membrane-based CO2 capture system. We have also prepared plate-to-frame modules, based on these membranes, showing high CO2 flux of 5 m3/h, for pilot plant demonstration.

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