DISPERSION CHARACTERISTICS OF PAA (POLYACRYLIC ACID) FOR TUBE FOULING CONTROL IN NUCLEAR POWER PLANT

摘要

Fouling of corrosion products in thermal exchange tube depress the thermal performance of the power plants. Dispersant injection was applied to reduce the accumulation of the corrosion products in power plants. Polyacrylic acid (PAA) is studied to evaluate the dispersion efficiency in various conditions. Dispersion efficiency is tested using turbi-scan apparatus(a settling test procedure). A colloidal suspension of the corrosion product oxide (1-10000 ppm magnetite), containing PAA at various concentration was prepared in the water solution (>17 MΩ) to compare the settling behavior in various condition. The pH was controlled at 9.7~9.8 by using ETA. The dispersion property of the magnetite solution depends on the PAA and magnetite concentration, the ratio of PAA to magnetite, and the settling time. Based on the test results, PAA significantly influences the dispersion stability of magnetite power and it is considered that PAA can be applicable for fouling control in power plants, but the optimization of the dispersion variables should be established.