Effect of Ferric Chloride on Silica Fouling

Abstract

This study presents the results of an experimental investigation of the effects of Fe3+ ion in aqueous solution on silica fouling of heat exchanger and assesses the relative effect of Fe3+, Na+, and K+ ions on silica fouling. Experiments were conducted at 165–125°C, 1.58 MPa, and under turbulent flow conditions. It was shown that adding a few ppm of Fe3+ into silica solution was sufficient to formulate chemical coagulation and deposition of silica colloidal particles, which in turn caused a significant increase in the fouling rate. It was also observed that when Fe3+ was added to the silica solutions containing either Na+ or K+ ions, the fouling behaviors were found to be similar. Thus Fe3+ was found to be dominant over Na+ and K+ ions in its effects on silica fouling.