Silica analyzers in modern power plants keep operators aware of harmful silica concentrations in the water-steam turbine cycle. In the boiler, silica forms silicate deposits that interfere with heat transfer and are very difficult to remove. In the turbine, silica deposits on the blades and causes drastic decreases in efficiency. Power plants with high pressure boilers closely monitor silica concentrations to avoid these problems.
Plants monitor silica with online analyzers, grab-sample testing, or some combination of the two. Both options are expensive. Online analyzers tend to have high capital and maintenance costs. Just the cost of the reagents can exceed $2000 per year per analyzer.
Analyzing grab samples can take 1/2 hour or more of valuable operator time just to test one batch of samples. Taking grab samples for analysis prior to startup often results in start-up delays of 15 to 30 minutes. Even this short delay for a 550-megawatt plant can deny revenue of $5,000 to $10,000 a day. With more than 100 warm start-ups a year, these dollar savings quickly add into the millions per year.