ASSUMPTION OF BOILER SCALE GROWTH RATE IN OXYGENATED WATER TREATMENT

For an evaluation of boiler scale growth in the oxygenated water treatment (OWT), after chemical state analyses of boiler scales sampled from utility boilers in which the OWT was used, the boiler scale growth mechanism was simulated with an iron oxide double layer model. As a result of the chemical state analyses, it was found that the OWT boiler scale consisted of iron oxide double layers of which the outer layer contained significant levels of hematite (Fe₂O₃) and the inner layer contained significant levels of magnetite (Fe₃O₄) instead of hematite. In the simulation with the double layer model the scale growth rate used correlated well with those observed in the laboratory loop and the utility boiler.