Mixed-conducting perovskite membranes

J.E. ten Elshof, H.J.M. Bouwmeester and H. Verweij, Oxidative Coupling of Methane in a Mixed-Conducting Perovskite Membrane Reactor , Appl. Catal. A, 130 195-212 (1995). 

M. van der Haar, Mixed-Conducting Perovskite Membranes for Oxygen Separation, Ph.D. Dissertation, Universiteit Twente, The Netherlands, 2001. 

The mixed-conducting perovskite oxides have attracted particular interest for use as dense ceramic membrane to control partial oxidation of methane to C2 products or syngas. Such a process bypasses the use of costly oxygen since air can be used as oxidant on the oxygen-rich of the membrane. 

The considerations in this chapter were mainly prompted by the potential application of mixed-conducting perovskite-type oxides to be used as dense ceramic membranes for oxygen delivery applications, and lead to the following general criteria for the selection of materials... 

The perovskite-type ceramic membranes have attracted much attention from major chemical and petrochemical companies in the USA. Companies currently involved in the development of the mixed-conducting ceramic membranes include Air Products, Praxair, BP and Amoco. The largest currently existing consortium developing this technology is headed by Air Products and sponsored by... 

Zhang, K., Sunarso, J., Shao, Z., Zhou, W Sun, C., Wang, S., and Liu, S. (2011) Research progress and materials selection guidelines on mixed conducting perovskite-type ceramic membranes for oxygen production. RSC Adv., 1, 1661-1676. 

Li, H., Zhu, X., Liu, Y., Wang, W., and Yang, W. (2014) Comparative investigation of dual-phase membranes containing cobalt and iron-based mixed conducting perovskite for oxygen permeation. /. Membr. ScL, 462,... 

Ito, W., Nagai, T., and Sakon, T. (2007) Oxygen separation from compressed air using a mixed conducting perovskite-type oxide membrane. Solid State Ionics, 178, 809 816. 

Figure 9.12 Temperature dependence of the oxygen permeation fluxes through various mixed-conducting membranes, made of perovskite-related compounds with predominant electronic conductivity, under fixed oxygen chemical potential gradients...

A series of perovskite compositions were synthesized using oxides and carbonates of the cations by conventional ceramic process. The synthesized powders were characterized using powder x-ray diffraction technique to ensure phase purity. Conductivity measurements were made in H2-H2O atmosphere to determine proton conductity. As the perovskite compositions are inherently mixed conducting, the transference numbers for proton and electron conduction were also determined by varying the partial pressures of hydrogen and steam across the membrane. 

Composite membranes also employ dense cermets fabricated by sintering together mixed powders of metal and ceramic [10-12], Examples include powders of Pd and its alloys sintered with powders of perovskites [11,12], niobium sintered together with AI2O3 [12], and nickel sintered with proton-conducting perovskites. Layers of dense cermets, 25-100 xm thick, are supported by porous ceramic tubes. Cermets employing chemically reactive metals, Nb, Ta, U, V, Zr, and their alloys, are typically coated with Pd and alloys thereof [11,12],... 

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