Simultaneous CO2 and O2 separation coupled to oxy-dry reforming of CH4 by means of a ceramic-carbonate membrane reactor for in situ syngas production

Concurrent and modulated separation of CO2 and O2 by a fluorite/perovskite‐based membrane

“…This behavior can be attributed to both the presence of electronic conduction and the thermal activation of the ionic transport mechanisms in the ceramic material, which are directly related to the transport of species. 13,25,36 It is noticeable that the CO 2 :O 2 molar ratio change from about 2.09 at 850°C to 3.14 at 950°C. In this sense, it is important to keep in mind that Equation ( 1) is an electrochemical reaction that involves electronic conductivity; therefore, the constant CO 2 :O 2 2:1 ratio could be expected only for a metal-based membrane.…”

“…The observed behavior is attributed to the presence, redistribution, or even loss of the excess of carbonates that remained on the membrane surface. 13,36,40 Once the steady state was reached, a remarkably stable and simultaneous separation of CO 2 and O 2 is observed, with permeance values of 0.72 × 10 −7 and 0.26 × 10 −7 mol m −2 s −1 Pa −1 , respectively. Once again, it is remarkable that different from metal-carbonate membranes wherein the CO 2 :O 2 molar ratio in the permeate is about 2 at any temperature (according to Equation 1) in the studied fluorite/perovskite-based membrane, this ratio is to about 2.7 at 875°C.…”

“…Finally, dense dual-phase membranes were obtained by direct infiltration of partially sintered supports using a eutectic molten carbonate mixture composed of Li 2 CO 3 /Na 2 CO 3 / K 2 CO 3 with a percent molar ratio of 42.5/32.5/25.0, respectively, following the previously reported method. 13 This ternary molten carbonate was chosen because it is a eutectic carbonate mixture with a low melting point of about 397°C. This property facilitates the infiltration process at a relatively low temperature.…”

“…In the aforementioned case, rich mixtures of H 2 /CO gas (syngas) have been successfully obtained. [13][14][15] Metal-carbonate membranes, wherein the metal phase is stainless steel, have been reported. In this case, CO 2 is separated at intermediate temperatures (500-650°C) under an oxygen transmembrane pressure difference.…”

“…9 Pr 0.1 O 2-δ -40 wt% Pr 0.6 Sr 0.4 Fe 0.5 Co 0.5 O 3-δ (hereinafter 60CP-40PSFC) were prepared via the so-called one-pot method, which is based on the combined EDTA/citrate complexing method previously described. 13,31 First, an aqueous solution containing stoichiometric amounts of the Ce(NO 3 ) 3 Second, the complexing agents EDTA and monohydrated CA were added to the solution of the nitrates according to a molar ratio of EDTA:CA:total metallic cations of 1:1:1. The molar concentration of the metallic cations was 200 mM, and the pH was adjusted to 6 by adding ammonium hydroxide (J.T.…”