Abstract
Materials failures are likely to remain an ongoing problem in FGD systems. Some parts of the system, such as outlet ducts, present extreme materials selection challenges. Other unavoidable problems will continue to occur because the actual environmental conditions are unexpectedly worse than those for which the material was selected. For example, this can occur when changes in regulatory policy mandate drastic changes in the operation of existing systems.
However, many failures are preventable in the design and construction phase. About half of the failures of the first 17 components studied in an EPRI-sponsored FGD materials failure analysis project resulted, at least partially, from a breakdown in the corrosion engineering process.
The most common breakdown was the failure to implement adequate quality assurance programs to be sure that the specified materials were correctly installed under the difficult conditions of field construction. Another major breakdown was specification of materials inconsistent with conservative materials engineering, given the service conditions which were known, or foreseeable, at the time that the design was finalized.
Anecdotal accounts of some of these failures are presented in the hopes of increasing the FGD design and utility engineer's awareness of this controllable aspect of the FGD corrosion problem.
