Modeling and Parametric Analysis of Hollow Fiber Membrane System for Carbon Capture from Multicomponent Flue Gas Rajab Khalilpour and Ali Abbas School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, Australia Zhiping Lai and Ingo Pinnau Advanced Membranes and Porous Materials Center KAUST, Thuwal, Saudi Arabia DOI 10.1002/aic.12699 Published online August 12, 2011 in Wiley Online Library (wileyonlinelibrary.com). The modeling and optimal design/operation of gas membranes for postcombustion carbon capture (PCC) is presented. A systematic methodology is presented for analysis of membrane systems considering multicomponent flue gas with CO 2 as target component. Simplifying assumptions is avoided by namely multicomponent flue gas represented by CO 2 /N 2 binary mixture or considering the co/countercurrent flow pattern of hollow-fiber membrane system as mixed flow. Optimal regions of flue gas pressures and membrane area were found within which a technoeconomical process system design could be carried out. High selectivity was found to not necessarily have notable impact on PCC membrane performance, rather, a medium selectivity combined with medium or high permeance could be more advantageous. V V C 2011 American Institute of Chemical Engineers AIChE J, 58: 1550–1561, 2012 Keywords: carbon capture, membrane, multicomponent gas, modeling, parametric analysis Introduction Avoiding CO 2 emissions is seen as imperative, and gov- ernments have recognized this as a key objective toward curbing effects of extreme weather, higher temperatures, worsening droughts and floods, and rising sea levels. Fossil fuels are the main contributors for CO 2 emissions. As such, carbon capture and storage (CCS) is viewed as a solution and a bridge from the current fossil fuel-based energy sys- tem to one that has near-zero carbon emissions. The premier interest in implementation of CCS projects is the large CO 2 sources, e.g., power plants accounting for about 78% of worldwide large stationary CO 2 sources. 1 There are three main approaches to capturing CO 2 from power plants; precombustion, oxyfuel combustion and postcombustion. Comprehensive descriptions of these processes can be found elsewhere. 2–3 Although oxyfuel and precombustion technolo- gies are studied extensively to be applied into new-build power plants, postcombustion (PCC) may be the most acces- sible option for retrofitting existing power plants due to mini- mum changes required to the existing plant. 4 A few technologies have been discussed for PCC; i.e., sol- vent-based absorption-desorption, 5 membrane, adsorption 6–7 and mineralization. 8 Solvent-based PCC although being the best available technology (BAT), is not a long-term desired technology for PCC due to its high-energy penalty for sol- vent regeneration. 5 Membrane-based PCC (MPCC) is one of the technologies that may have good potential to compete with solvent tech- nology although currently being under very controversial dis- cussions. The main advantages of membrane separation over other technologies include compactness, modularity, and ease of installation by skid-mounting, ability to be applied in remote areas such as offshore, flexibility in operation and maintenance and in most cases lower capital cost as well as lower energy consumption. 9 Carbon dioxide separation using membranes is widely addressed in the context of natural gas sweetening where the gas coming from the well contains CO 2 and H 2 S and is required to be reduced to pipeline specifications (CO 2 ¼ 2% and H 2 S ¼ 4 ppm). 10–11 However, this does not necessarily certify the practicality of using membranes for separation of CO 2 from flue gas due to the CH 4 -CO 2 and CO 2 -N 2 systems having differences in selectivity and in molecular size ratios of the binary components as well as due to different impacts of adsorption or capillary condensation effects. The pioneer work on CO 2 /N 2 separation may be traced back to the article by Kawakami et al. 12 They studied the impact of blending a low-permeable glassy polymer (cellu- lose nitrate) with a plasticizer membrane (poly (ethylene gly- col), PEG) on CO 2 /N 2 separation. The interesting point of this research was that the authors did not have clear ideas for industrial applications of CO 2 /N 2 separation and only projected that the separation of CO 2 from N 2 might be used ‘‘in order to recover carbon resources or to control CO 2 con- centration in an artificial atmosphere’’. It was mainly after the United Nation’s Earth Summit, held June 1992 in Brazil, that researches on different alter- native approaches, including membrane, for separation of CO 2 from flue gas (PCC) accelerated due to the high- commercial value forecast. Since then various researches Correspondence concerning this article should be addressed to A. Abbas at ali. abbas@sydney.edu.au. V V C 2011 American Institute of Chemical Engineers 1550 AIChE Journal May 2012 Vol. 58, No. 5