Dual-phase membranes

Another example of the high-temperature membrane technologies is a dual-phase membrane developed at Columbia University, which consists of solid oxide and molten carbonate. This membrane technology takes advantage of oxide and carbonate ionic transport. At the face of the membrane exposed to the high concentration of COz, carbonation dioxide... 

Fig. 10.1. Different membrane concepts incorporating an oxygen ion conductor (a) mixed conducting oxide, (b) solid electrolyte cell (oxygen pump), and (c) dual-phase membrane. Also shown is the schematics of an asymmetric porous membrane (d), consisting of a support, an intermediate and a barrier layer having a graded porosity across the membrane.

As is clear solid oxide electrolytes are not useful for applications as oxygen separation membrane, unless operated with external circuitry (oxygen pump) or as a constituent phase of a dual-phase membrane. Both modes of operation, classified in this paper as electrochemical oxygen separation, are briefly discussed in Section 10.4.3. But we first start with a discussion of the models that have been developed to describe the oxygen semi-permeability of solid oxide... 

Barnes and Wang [48,49] studied the performance of both sandwich and tubular-type dual-phase membrane gas-di sion separators in the determination of As(V) by hydride generation ICP-OES, and obtained better detection limits with a sandwich design, while both were found to be superior to using a gas-expansion separator. Their results seem to suggest that dual-phase membrane separators are better suited at least for combination to ICP-OES systems in comparison to gas expansion separators, but further research efforts may be necessary to reach decisive conclusions. 

There are several advantages to using a dual-phase membrane over a singlephase mixed electronic ionic conductor. These include the fact that the ionic conductors such as YSZ are much more chemically and thermally stable compared to most perovskites. Thus, dual-phase membranes are Ukely to be able to tolerate the harsh conditions of an oxygen separation device. They also show good tolerance to both CO2 and steam. The difficulty comes in the selection of an electronically conducting material. The cost of noble metals makes their incorporation into commercial devices unlikely. Therefore, the electron-conducting phase is Umited to a... 

Figure 1 Externally Short Circuited Cells and Dual Phase Membranes...

Table 8 Oxygen Flux Results for Dual Phase Membrane Discs at 1100 C... 

An alternative to the OTM can be dual phase membranes. Here a nanoscale ion conductor is in intimate contact with an electron conductor. The first dual phase membranes were made of oxide conductors and noble metal ... 

The membranes used in analytical separation processes are usually single- or dual-phase membranes. 

Zhu X, Li Q, He Y, Cong Y and Yang W (2010), Oxygen permeation and partial oxidation of methane in dual-phase membrane reactors , J Membr Sci, 360, 454-460. 

Zhu, X., Yang, W. (2011). Critical factors affecting oxygen permeation through dual-phase membranes. In Inorg. polym. compos, membr. struct, funct. other correl (1st ed.). (pp. 275-293). Elsevier BV. 

Anderson, M., Lin, Y. S. (2010). Carbonate-ceramic dual-phase membrane for carbon dioxide separation. Journal of Membrane Science, 357, 122—129. 

Weishen Yang et al. Design and Experimental Investigation of Oxide Ceramie Dual-phase Membranes, Journal of Membrane Science, 120-130,394-395 (2012). 

The development of high-temperature membrane solutions for CO2 capture relying on perovskite membranes requires a proper description of mass transfer within the membranes. To this aim, this chapter provides a compilation of models accounting for mass transfer within single- and dual-phase membranes, as... 

Dong, X., Ortiz Landeros, J., and Lin, Y.S. (2013) Asymmetric tubular ceramic-carbonate dual phase membrane for high temperature CO2 separation. Chem. Commun, 49,9654-9656. 

Rui, Z., Anderson, M Lin, Y.S., and Li, Y, (2009) Modeling and analysis of carbon dioxide permeation through ceramic-carbonate dual-phase membranes,... 

Lu, B, and Lin, Y,S. (2014) Asymmetric thin samarium doped cerium oxide-carbonate dual-phase membrane for carbon dioxide separation, Ind. Eng. Chem. Res., 53, 13459-13466,... 

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