Surface oxygen vacancy and oxygen permeation flux limits of perovskite ion transport membranes

Anton Hunt, Georgios Dimitrakopoulos, Ahmed F. Ghoniem

Research output: Contribution to journalArticlepeer-review

29 Scopus citations

Abstract

© 2015 Elsevier B.V. The mechanisms and quantitative models for how oxygen is separated from air using ion transport membranes (ITMs) are not well understood, largely due to the experimental complexity for determining surface exchange reactions at extreme temperatures (>800°C). This is especially true when fuels are present at the permeate surface. For both inert and reactive (fuels) operations, solid-state oxygen surface vacancies (δ) are ultimately responsible for driving the oxygen flux, JO2. In the inert case, the value of δ at either surface is a function of the local PO2 and temperature, whilst the magnitude of δ dictates both the JO2 and the inherent stability of the material. In this study values of δ are presented based on experimental measurements under inert (CO2) sweep: using a permeation flux model and local PO2 measurements, collected by means of a local gas-sampling probe in our large-scale reactor, we can determine δ directly. The ITM assessed was La0.9Ca0.1FeO3-δ (LCF); the relative resistances to JO2 were quantified using the pre-defined permeation flux model and local PO2 values. Across a temperature range from 825°C to 1056°C, δ was found to vary from 0.007 to 0.029 (
Original languageEnglish (US)
Pages (from-to)248-257
Number of pages10
JournalJournal of Membrane Science
Volume489
DOIs
StatePublished - Sep 2015
Externally publishedYes

Fingerprint

Dive into the research topics of 'Surface oxygen vacancy and oxygen permeation flux limits of perovskite ion transport membranes'. Together they form a unique fingerprint.

Cite this