Environmental effects on microstructure and strength of SiC-based hot gas filters

The aggressive process environment in advanced coal-fired power generation systems causes microstructural changes in the ceramic hot gas filters used to clean the fuel gas. Changes in microstructure and their effect on strength were studied for commercial SiC-based clay bonded hot gas filters exposed to high temperature, water vapour and gaseous sodium compound. Exposures caused significant crystallization of the binder phase and oxidation of SiC. Loss in strength also occurred. The microstructural changes and their effect on strength are discussed.