Application of the Dispersant for Sludge Removal at the YGN Unit 6

摘要

To remove iron sludge, KHNP-CRI applied the dispersant(PAA) at Yonggwang Unit 6. Dispersant Injection term is about 4 months. The full scale PAA trial at YG unit 6 began at 10:30 February 1, 2012 with the injection of 0.5% solution of PAA at about 6 l/hr. The initially injected solution yielded a nominal average PAA concentration 0.25 ppb in the final feedwater with the plant operating at 100% power. During the course of the trial, we are measured the change of water chemistry in the secondary system and effect of iron sludge removal in the SG. And in addition, we analyzed the fouling factor for the thermal performance. PAA appeared to have a small effect on the measured blowdown cation conductivity, raising it by 0.20 uS/cm. Total organic carbon has no change. The iron removal rate at the Hotleg, downcomer and regenerated thermal exchanger is from 1.45 to 3.63 and 7.29 to 23.30 ppb, 42.6to 542.7 ppb respectively. And due to the removal iron, the analysis of total fouling coefficient is raising a little.