The Use of (Ca,Sr)(Al,Fe) Ox Brownmillerite Materials for ITM Syngas Membranes
Publication Date: 2003-Sep-24
The IP.com Prior Art Database
The Use of (Ca,Sr)(Al,Fe)Ox Brownmillerite Materials for ITM Syngas Membranes
Synthesis gas, a mixture of hydrogen and carbon monoxide, can be produced by oxidatively-reforming a hydrocarbon-containing stream which passes on one side of a non-porous, mixed conducting ceramic membrane, with oxygen from a hot, oxygen-containing gas, preferably air, which passes on the other side of the ceramic membrane. These membranes, known in the art generically as ion transport membranes (ITMs), utilize an oxygen chemical potential gradient across the membrane to cause oxygen ions to migrate through the membrane.
Membranes can be fabricated as tubes or flat plates that are arranged in modules for efficient contact with the hot air and hydrocarbon-containing streams. Synthesis gas and nitrogen-enriched non-permeate products are withdrawn from the modules. A comprehensive review of ion transport membranes is given by M. Stoukides in Catalysis Reviews - Science and Engineering, 42(1&2), 2000.
Many compositions have been tested as prospective materials of fabrication for ITM Syngas membranes. Studies performed by Eltron Research have focused attention on brownmillerites as a class of materials of interest. The mineral brownmillerite has a chemical composition of CaAl0.5Fe0.5O5 and is well known in the art. By substituting part of the Ca with Sr, the total conductivity of the resulting materials increased while the brownmillerite structure was maintained. An increase in total conductiv...