Online ion chromatography: Monitoring corrosive anions in ultra-supercritical steam-electric power plants

Nuclear power plant cooling tower
Corrosive anions are a notorious enemy of steam-electric power plants, eating away at pipes, turbine blades, and rotors. Continuous monitoring of those anions down to the ultra-trace range is therefore a must in any such facility.

Online ion chromatography provides the technology to meet this challenge, both in terms of sensitivity and robustness, as a project from Taiwan Power Company demonstrates.

At two of their Taiwan sites, Taiwan Power Company is planning to expand its coal-fired power plants to include three ultra-supercritical 800-megawatt units in Linkou, and two in Talin. They are scheduled to go into operation between 2016 and 2021 and will rely on ion chromatography systems from Metrohm for online monitoring of critical anions.

Since even traces of those anions can have devastating consequences in such facilities, detection limits of as low as 0.5 to 5 µg/L (about a hundred times lower than in subcritical power plants) need to be met in ultra-supercritical plants.

The Metrohm Online IC system to be implemented features combined Inline Preconcentration and Inline Matrix Elimination. Online analysis takes place in the process itself, and no sampling is required as the system is fed directly and continuously via a bypass in the process – in this case, at the water-steam circuit. More information is available from a technical article (MI-2014-2-KA-2) and from Metrohm.