Performance and stability of porous ceramic candle filters during PFBC operation

Westinghouse's involvement at the American Electric Power (AEP) pressurized fluidized-bed combustion (PFBC) Tidd demonstration plant has recently identified critical issues pertaining to the life of monolithic and fiber reinforced porous ceramic filter elements, as well as process control parameters that impact commercialization of the hot gas filtration technology. Although the nonoxide filter materials primarily undergo oxidation and/or creep, and the oxide-based matrices experience thermal fatigue, both materials exhibit an initial loss of bulk strength, but achieve a conditioned or stabilized strength during operation in the PFBC environment. Continued operation will, however, be required to demonstrate extended viability of the conditioned porous ceramic filter materials in process controlled, advanced coal-fired applications.