Pushing the limits of intensified CO 2 post-combustion capture by gas– liquid absorption through a membrane contactor E. Chabanon a, b , R. Bounaceur a , C. Castel a , S. Rode a , D. Roizard a , E. Favre a, * a LRGP-CNR SUMR 7578, Université de Lorraine 1, rue Grandville, 54001 Nancy, France b Université de Lyon, F-69622 Lyon, France; Université Lyon 1, Villeurbanne, Laboratoire d'Automatique et de Génie des Procédés (LAGEP) - CNRS, 43 bd du 11 Novembre 1918, 69100 Villeurbanne, France A R T I C L E I N F O Article history: Received 20 December 2014 Received in revised form 25 February 2015 Accepted 4 March 2015 Available online 7 March 2015 Keywords: Intensification Gas absorption Membrane contactor Energy CO 2 capture A B S T R A C T The possibility to maximize the intensification (i.e., volume reduction) of post-combustion carbon dioxide capture by chemical absorption in a monoethanolamine (MEA) solution using a membrane contactor module is reported. The influence of MEA concentration (20–90 wt%) and temperature (293–333 K) on the CO 2 capture ratio achieved by a PTFE hollow fiber membrane contactor has been investigated with a CO 2 /N 2 (15/85 vol%) gas mixture and the experimental results modeled. It is shown, through a systematic parametric analysis, that the intensification factor of the absorption unit, defined as the ratio of the CO 2 volumetric absorption capacity of the membrane contactor and of the packed column (taken at 1 mol CO 2 m 3 s 1 ), can be largely increased when a concentrated (70 wt%) MEA solution at 333 K is used. A volume reduction up to a factor 9, together with a lower energy penalty due to pressure drop effects (kWh per ton of captured CO 2 ) is potentially obtained compared to packed column performances, when a large enough membrane mass transfer coefficient is achieved (i.e., larger than 10 4 m s 1 ). The remaining challenges which are required in order to develop this level of performances at industrial scale based on the existing membrane contactor materials are discussed. ã 2015 Elsevier B.V. All rights reserved. 1. Introduction The limitation of the global climate change, i.e., the decrease of CO 2 anthropogenic emission, is one of the main challenges for environmental policies [1]. Therefore, CCS (for carbon capture and storage) is intensively investigated through different strategies and processes to reduce CO 2 emissions from large fossil fuel combus- tion units such as power plants (coal fired, natural gas combined cycle . . . ) [2,3]. Three major steps are involved in order to achieve that purpose: first, CO 2 capture from flue gas (by using a separation process) and compression, then transport (generally by pipe) and finally geological storage in a specific location. The final aim of the CO 2 capture step is the concentration of CO 2 flux, typically up to 90% purity, in order to reduce the storage place required; the capture + compression operation is the most expensive step with 60–80% of the total cost of the overall CCS chain [4,5]. Hence, many studies reported in the literature focus on designing the CO 2 capture process which will be the most efficient in terms of size, energy penalty, operating cost (OPEX) and capital cost (CAPEX). Until now, the CO 2 post-combustion capture (i.e., direct capture from the flue gases) is the most attractive strategy as it is the only one allowing the retrofit of the power plants in operation [6]. The reference process is a gas–liquid absorption process using a packed column and a 30 wt% monoethanolamine (MEA) mass fraction in aqueous solution as liquid phase. In this kind of process, a chemical reaction between MEA and CO 2 is used to enhance the CO 2 absorption by the liquid phase in an absorption unit (Fig. 1). A water wash at the top of the absorption unit in order to limit the MEA emissions to the atmosphere, and an intermediate inter cooling heat exchanger, shown in Fig. 1, are often included. The chemical reaction is reversible by heating the liquid phase. The major part of the energy requirement, which is around 3.5 GJ per ton of CO 2 (thermal basis) for baseline operating conditions [4,5], is used to regenerate the liquid phase solvent (MEA and 70 wt% of water) by steam stripping in a second unit. The solvent is recycled in the absorption column after regeneration and cooling (Fig. 1). A very large number of studies addressed the challenge of decreasing the size of the capture unit and/or improving the energy efficiency of the process [3]. Basically, these two targets can be tackled either through innovative solvent formulations and/or process design strategies (e.g., energy integration, column intercooling, optimized operating conditions . . . ) [4,7]. More * Corresponding author. Tel.: +33 383 17 53 90. E-mail address: eric.favre@univ-lorraine.fr (E. Favre). http://dx.doi.org/10.1016/j.cep.2015.03.002 0255-2701/ ã 2015 Elsevier B.V. All rights reserved. Chemical Engineering and Processing 91 (2015) 7–22 Contents lists available at ScienceDirect Chemical Engineering and Processing: Process Intensification journal homepa ge: www.elsev ier.com/locate/cep