Which compounds are considered scale forming solids in boiler systems?

Which compounds are considered scale forming solids in boiler systems?

• A. Calcium, Sodium, Chlorine
• B. Calcium, Magnesium, Silica
• C. Magnesium, Iron, Barium
• D. Calcium, Sodium, Sulfate

Answer: (B)

In boiler systems, scale forming solids are primarily those compounds that precipitate from water as the temperature and pressure increase. These compounds can lead to the formation of scale on heat transfer surfaces, which diminishes efficiency and can lead to equipment failure if not managed properly. The correct choice includes calcium, magnesium, and silica. Calcium and magnesium are multivalent cations that can form insoluble salts with carbonate, sulfate, or phosphate ions when their concentrations in the water exceed certain levels. Silica, which can be present in water, tends to precipitate and form scale at higher temperatures. This trio is known for contributing significantly to the formation of hard scale, which is resistant to removal and can create substantial operational issues within boiler systems. The other options do not encompass the key compounds known for scale formation to the same extent. While sodium and sulfate can be part of water chemistry in boiler systems, they do not significantly contribute to scale compared to calcium, magnesium, and silica, which are critical indicators of scaling tendencies.

In boiler systems, scale forming solids are primarily those compounds that precipitate from water as the temperature and pressure increase. These compounds can lead to the formation of scale on heat transfer surfaces, which diminishes efficiency and can lead to equipment failure if not managed properly.

The correct choice includes calcium, magnesium, and silica. Calcium and magnesium are multivalent cations that can form insoluble salts with carbonate, sulfate, or phosphate ions when their concentrations in the water exceed certain levels. Silica, which can be present in water, tends to precipitate and form scale at higher temperatures. This trio is known for contributing significantly to the formation of hard scale, which is resistant to removal and can create substantial operational issues within boiler systems.

The other options do not encompass the key compounds known for scale formation to the same extent. While sodium and sulfate can be part of water chemistry in boiler systems, they do not significantly contribute to scale compared to calcium, magnesium, and silica, which are critical indicators of scaling tendencies.