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Thermochemical Characterization of Gas separation membranes

Membrane technology constitutes a promising approach to reduce the CO2 emissions of fossil-fired power plants. CO2 resulting from the combustion of fossil energy carriers can be separated by means of different separation technologies: pre-combustion, post-combustion and oxy-fuel.

In the pre-combustion process, the fossil energy carrier is partially oxidized with pure oxygen. Using water vapour, the resulting CO is then converted into CO2 and H2. The hydrogen is used for further energy production. In the post-combustion process, the CO2 is separated after the combustion of the fossil energy carrier in air. When the fossil energy carrier is combusted in pure oxygen, the procedure is referred to as the oxy-fuel process. In this case, the flue gas consists mainly of CO2 and water vapour, which can easily be separated by means of condensing the water vapour.

Membrane technology is a promising approach to reduce the costs of producing pure oxygen in comparison to cryogenic air decomposition. High-temperature ceramic membranes that conduct both electrons and oxygen ions are regarded as potential membrane materials. These membranes must exhibit high oxygen permeability, high mechanical stability and must resist corrosion caused by aggressive gases.

Potential membrane materials for the pre-combustion and oxy-fuel process are studied in terms of their thermochemical properties as part of various projects (OXYMEM, MEM-BRAIN, MEM-OXYCOAL) in cooperation with different project partners from industry and research. For this purpose, analyses are carried out by means of thermogravimetry, high-temperature dilatometry and differential thermal analysis, in gases with and without CO2. The permeability and corrosion resistance of the materials are also studied.

Corroded ceramic membraneCorroded ceramic membrane

Specimen holder with membraneSpecimen holder with membrane

CO2-emission free power plantsCO2-emission free power plants