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

Abstract

In this paper, it is reported the fabrication of a new dense ceramic-molten carbonate membrane used for the selective separation of carbon dioxide (CO 2 ) and oxygen (O 2 ) at elevated temperatures (850-950°C). First, it was chemically synthesized a fluorite/perovskite ceramic oxide with mixed ionic-electronic conduction properties and general formula Ce 0.9 Pr 0.1 O 2-δ /Pr 0.6 Sr 0.4 Fe 0.5 Co 0.5 O 3-δ (CP-PSFC, 60:40 wt%) by the citrate-ethylene-diamine-tetra acetic acid (EDTA) route. Then, a disk-shaped porous ceramic support partially sintered was infiltrated with a ternary mixture of molten salts of Li 2 CO 3 /Na 2 CO 3 /K 2 CO 3 composition. The permeation measurements at high temperatures suggest a concurrent separation of both species CO 2 and O 2 . The system exhibits high permeance of CO 2 and O 2 by rising to maximum values of 2.17 × 10 −7 and 0.69 × 10 −7 mol m −2 s −1 Pa −1 , respectively at 950°C. Moreover, the possibility of modulating the permeate CO 2 :O 2 ratio is envisaged by changing the fluorite to perovskite proportion in the membrane composition. The stability performance of the obtained membrane was studied under a long-term permeation test. It exhibits a remarkable thermal and chemical stability during 110 h at 875°C. This way, it corroborated the proposed new ceramic phase's excellent properties for the fabrication of supported ceramic-molten carbonate membranes.