High performance composite CO2 separation membranes

Abstract

The CO 2 permeation of composite membranes obtained by impregnation of molten alkaline carbonates into a Gd-doped ceria ceramic skeleton was tested using several gas mixtures with up to 50 vol% CO 2 as feed gas and Ar in the membrane permeate side. Experiments performed in the 550-850 °C temperature range showed high permeation rates reaching 0.6 ml.min -1 .cm -2 at 850 °C for the higher CO 2 content. These values exceed those often reported for similar membranes and conditions. Furthermore, the characterization of the ceramic skeletons and composite membranes by impedance spectroscopy (in air at low temperature) could be used to estimate the temperature where dual oxide and carbonate ionic transport are balanced (around 800 °C). The inherent shift in the CO 2 permeation activation energy is shown to match closely this prediction.

Benchmarking the ambipolar conductivity of composite electrolytes for gas separation membranes

“…R is a resistor, while CPE is a constant phase element. Matching performance of oxide skeletons alone and two phase composites confirmed this result [12]. Here, only key issues will be recalled to explain data handling.…”

“…Thus, the conductance of the carbonates in the composite can be estimated from the cell total conductance, after deduction of the (marginal) estimated parallel conductance of the CGO skeleton. Enhanced accuracy in the determination of G CGO can be obtained when the composite processing route involves two steps, firstly the consolidation of the ceramic skeleton and afterwards the impregnation with MCs (e.g., see [9][10][11][12]). Furthermore, both sets of data (CGO and NLC conductance) take into consideration phase content and effective microstructure, since derived from actual measurements.…”

“…In these membranes, the usual description is that motion of carbonate ions (and/or alkaline metal ions) is electrically balanced by a flow of oxide ions, yielding a net flow of CO 2 [6][7][8][9][10][11][12][13]. In these membranes, the usual description is that motion of carbonate ions (and/or alkaline metal ions) is electrically balanced by a flow of oxide ions, yielding a net flow of CO 2 [6][7][8][9][10][11][12][13].…”

A highly selective PEGBEM-g-POEM comb copolymer membrane for CO2/N2 separation

“…Compared to other gas separation technologies such as adsorption, absorption, and cryogenics, membrane technology has many advantages including facile preparation processes, low energy cost, and remarkable reliability [1][2][3][4][5]. With these promising features, membrane technology has been a significant part of the strategy for the CO 2 removal industry and advanced commercial applications.…”

Electromotive Force (emf) Determination of Transport Numbers for Native and Foreign Ions in Molten Alkali Metal Carbonates

“…Using such dual-phase membranes, it is thus possible to separate CO 2 from a multicomponent gas stream (e.g. that also contains N 2 and/or H 2 ) at high temperature with high selectivity.There are already several reports on the effect of different ceramic phases (alumina, yttria-stabilized zirconia, gadolinia-doped ceria, lanthanum-strontium-cobalt-iron oxide) on the flux of the dualphase membranes, 5,7,8,10,13,14 wherein the influence of the microstructure, the ratio of the two phases, and the wettability of the ceramic surface were investigated. Other publications focused on modelling the above-mentioned properties of such dual-phase membranes in order to investigate the effect of pressure and the presence of oxygen in the flue gas on the surface reaction and bulk conductivity.…”