Abstract
Independent investigators documented corrosion mitigation strategies at power stations. The study was motivated by the fact that many alloy wet flue gas desulfurization (WFGD) absorbers of recent construction are experiencing premature failure from localized corrosion. The alloy of construction most affected by localized corrosion attack is UNS S32205 – a duplex stainless steel. The rate of attack has exceeded 500 mils per year (mpy) in forced oxidation WFGD service. A corrosion rate of this magnitude will lead to perforation of the absorber walls and floor in less than one year of service. The time to initiate localized attack can be as little as two to three months. Compounding the issue, UNS S32205 has seen perhaps the highest use for the fabrication of new WFGD absorbers in the United States.
The combination of high corrosion rates and widespread use of these alloys has created industry-wide concern for the designed service life as well as unexpected increases in the life cycle cost of emissions control equipment. The power industry responded to the aggressive attack of their assets by implementing corrosion mitigation strategies. The corrosion mitigation strategies reviewed in this paper are cathodic protection, internal fiber reinforced lining system, polishing of the internal alloy surfaces, and application of a high-alloyed wallpaper.
