Silica is widely distributed in nature, serving as a major component of minerals and rocks. It does not exist in a free state, but only in compound forms. Silicates have numerous types and complex structures, usually composed of silicon dioxide combined with metal oxides. This article focuses on silica control and water quality monitoring in boiler water, as detailed below.

Silicon compounds in water are a major cause of scale formation. Silicate scale has a complex chemical composition, mostly consisting of iron and aluminum silicate compounds. These compounds tend to deposit on the inner walls of boiler tubes with high heat load or poor water circulation, as well as on the blades of the low-pressure turbine cylinders. Scale has much lower thermal conductivity than metal, which impedes heat transfer, resulting in heat loss. Meanwhile, it causes local overheating and damage to the boiler. In addition, scale induces under-deposit corrosion on metal surfaces, compromising the safe operation of the boiler.

1.In power plant water treatment, ion-exchange resins are widely used to remove salts from water. Silicate ions have weak bonding affinity with anion resins, leading to silica leakage. Therefore, silica measurement at the outlet of anion beds and mixed beds is required to evaluate their operating performance.

2.For power plant steam-water monitoring, operators monitor silicate content in drum boiler water to assess water quality, and determine the opening of surface blowdown, frequency of bottom blowdown, and blowdown duration based on measured data.

3.Silicate monitoring also verifies whether water quality complies with relevant standards, preventing equipment malfunction or efficiency reduction caused by silica fouling.

In summary, online monitoring and analysis of silica in water are critically important. It not only reduces operational failures but also evaluates water quality in real time. The SiO2-8000 Online Silica Analyzer can be adopted for continuous real-time silica monitoring in water.