Abstract
This paper reports on the field test of the high-temperature corrosion monitoring sensor for boiler tubes in waste incinerators. The sensor, equipped with the electrode part for electrochemical measurement, were inserted in the boiler furnace in a municipal incineration plant and the parameters for the corrosion measurement were observed for 322 hours at 30-minute interval. The conditions for the measurement were as follows; material of working electrode: Alloy 625, gas temperature (T_<gas>): 560 to 650℃ (599℃ on average), metal temperature (T_<meial>): 510 to 560℃ (544℃ on average). In a set of measurement, the polarization resistance of Alloy 625 was evaluated by electrochemical impedance measurement first, and then the corrosion rate and the corrosion depth were calculated by simultaneous operation. The total corrosion depth observed with the corrosion sensor was 0.11 mm and this value was in error of only 0.06 mm against the accurate value obtained by measurement of the loss-of-size of the electrode with a micrometer. The observed data provides the contour map of the corrosion rate of Alloy 625 represented in the T_<metal>-T_<gas> coordinate system, useful for the corrosion protection and the material selection in waste incineration boilers.
