Steam-promoted CO2 flux in dual-phase CO2 separation membranes

Steam dissolving into molten carbonates through the formation of hydroxide ions could contribute to the permeation of CO2 in dual-phase membranes under certain conditions. In this work, ceria (CeO2) supported dual-phase membranes was fabricated and the effect of steam on the transport properties has been investigated by means of flux measurements. The results show an approximate 30% increase of the CO2 flux when 2.5% steam is introduced to the feed side, while an approximate 250-300% increase of the CO2 flux is observed when introducing the same amount of steam to the sweep side. These phenomena and transport mechanisms are explained by the theory of ambipolar permeation of CO2 via various combinations of charged species. (C) 2015 Elsevier B.V. All rights reserved.