High CO2 permeability in supported molten-salt membranes with highly dense and aligned pores produced by directional solidification

Autor: Evangelos I. Papaioannou, Greg A. Mutch, Josh J. Bailey, María Luisa Sanjuán, Rosa I. Merino, Matt D. R. Kok, L. Grima, W. Bucheli, Ian S. Metcalfe, Paul R. Shearing, Dan J. L. Brett, Patricia B. Oliete
Přispěvatelé: Ministerio de Economía y Competitividad (España), European Research Council, European Commission, Engineering and Physical Sciences Research Council (UK), Royal Academy of Engineering, Newcastle University
Rok vydání: 2021
Předmět:
Zdroj: Digital.CSIC. Repositorio Institucional del CSIC
instname
Zaguán. Repositorio Digital de la Universidad de Zaragoza
ISSN: 2016-7776
Popis: Composite molten salt-ceramic membranes are promising devices for high-temperature CO2 separation. Intensive material properties impact on separation performance as do membrane geometry (thickness) and microstructure (pore volume fraction, size, connectivity, and tortuosity factor). Although controlling pore size is considered somewhat routine, achieving pore alignment and connectivity is still challenging. Here we report the production of the first gas separation membrane using a porous ceramic matrix obtained from a directionally-solidified magnesium-stabilised zirconia (MgSZ) – MgO fibrilar eutectic as the membrane support. MgO was removed from the parent material by acid-etching to create a porous matrix with highly aligned pores with diameters of ~1 μm. X-ray nano-computed tomography of a central portion (~32,000 μm3) of the support identified ~21% porosity, with all pores aligned within 10° and ~76% percolating along the longest sampled length. Employing the matrix as a support for a carbonate molten salt, a high CO2 permeability of 1.41x10-10 mol.m-1.s-1.Pa-1 at 815 °C was achieved, among the highest reported for supported molten-carbonate membranes (typically 10-12 to 10-10 mol.m-1.s-1.Pa-1 at similar temperatures). We suggest that the high permeability is attributable to the excellent pore characteristics resulting from directional solidification, namely a dense array of parallel, micron-scale pores connecting the feed and permeate sides of the membrane.
The authors acknowledge the financial support from the Spanish Ministerio de Economía y Competitividad and Feder Funds under project MAT2016-77769R. L. Grima acknowledges financial support through grant BES-2017-079683 associated to the aforementioned project. The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement Number 320725 and from the Engineering & Physical Sciences Research Council (EPSRC) via grants EP/M01486X/1, EP/P007767/1 and EP/P009050/1. PRS acknowledges the Royal Academy of Engineering (CiET1718/59). PRS, DJLB, JJB and MDK acknowledge the support of The Faraday Institution (faraday.ac.uk; EP/ S003053/1). G. Mutch was supported by the Royal Academy of Engineering under the Research Fellowship Scheme and would like to thank the EPSRC for his Doctoral Prize Fellowship (EP/M50791X/1) and Newcastle University for a Newcastle University Academic Track (NUAcT) Fellowship. X-Ray CT acquisition and analysis was supported by UCL and EPSRC under EP/N032888/1. We thank the Servicio General de Apoyo a la Investigación-SAI (Universidad de Zaragoza) for technical support in X-ray diffraction and electron microscopy experiments, Rubén Gotor for technical assistance in sample preparation and R. Lahoz for laser-drilling the YSZ plate that serves as the membrane base.
Databáze: OpenAIRE
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