Silica Deposition Experiments:Past Work and Future Research Directions

Abstract

After 40 years of investigations silica scaling is qualitatively well understood, but reliable predictions of scaling under typical power station operating conditions are still not possible.

In this paper we review a few selected field silica scaling experiments undertaken primarily in New Zealand, which have involved measuring scaling rates. The aim is to provide insights into what can be learnt from such studies and to show that there is much more to understand about the scaling process.

Aging of water to allow silica polymerization has been shown to reduce scaling potential. Icelandic researchers have demonstrated that rapid cooling and dilution are very effective at suppressing deposition. We describe work underway at Wairakei to determine the effectiveness of this technique for New Zealand waters.