Oxygen separation perovskite membranes

Middelkoop, V., Chen, H., Michielsen, B., et al. (2014) Development and characterisation of dense lanthanum-based perovskite oxygen-separation capillary membranes for high-temperature applications. Journal of Membrane Science, 468, 250-258. 

Perovskite-structured oxides with high electronic and oxygen ion conductivities could be used as a membrane alternative to solid electrolytes for oxygen separation. In such materials, both oxygen ions and electronic defects are transported in an internal circuit in the membrane material. 

We will first consider the development activity which has occurred in the application of oxygen separation and collection. A wide range of materials has been examined in this area including perovskites, brownmillerites, fluorites and composites of various structures. There has also been progress in membrane architec-... 

There are two main approaches for fabricating oxygen separation membranes. The first is to use a mixture of two distinct materials - an oxygen-ion conductor such as doped zirconia, and an electron conductor such as a noble metal or a doped perovskite (see Fig. 6.1). The second approach is to use a material which is capable of conducting both oxygen ions and electrons (see Fig. 6.2). 

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... 

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

Air separation membranes are typically dense ceramic (typically perovskite) membranes, which selectively permeate oxygen in ionic form. Over the past two decades. Air Products (ITMs) and Praxair (oxygen transport membranes [OTMs]) have worked towards the commercial scale-up of these membranes for applications in power generation, gasification, and gas to liquid conversion [94]. Air Products has focused on a planar configuration, whereas Praxair on tubular membranes. 

J. Caspary, H. Wang, ). Caro, Hollow fibre perovskite membranes for oxygen separation. Journal of Membrane Science 2005, 258 (1/2), 1-4. 

Perovskite Membranes for High Temperature Oxygen Separation... 

Whereas most perovskite material have operation temperatures above 800 °C, our BCFZ perovskite hollow fiber membrane could be successfully used for oxygen separation from air between 400 and 500 °C (Figure 16.6). As Figure 16.6 shows, the oxygen permeation flux increases from 0.03 to 0.45 mL cm min as the temperature rises from 400 to 500 °C. However, in... 

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